Variants and Heterodox Chess Problem thread

[Paul Bonham]

Re: Variants and Heterodox Chess Problem thread

Your idea of 'limited resource elements' as a way to introduce (limited!?) complexity is intriguing, if such element(s) could seem natural to any chess variant they were introduced as part of. The example of double move(s), with restrictions, may or may not seem natural to some (most people, I would guess, may prefer strictly alternating moves in any sort of game

There are many versions of pool / billiards in which one player gets to continue playing shots as long as s/he manages to sink one or more balls of a particular type (solid, stripe, certain numbers). This does not keep players from wanting to play these versions.

Of course, in golf a player can make several shots in a row also, but that is a sign that s/he isn't playing very well! :)

One of my double-move restrictions was that a player may not make 2 or more double-moves consecutively, with the idea of preventing a player from securing an initial advantage with the game's first double-move and then forcing that advantage all the way to mate using all their double-moves consecutively. But there is an allure to that possibility, in that it enables a go-for-broke mode of play. And of course, the opponent could reply with his / her own consecutive double-moves, and might even spare one or two for a possible endgame if the first player fails to achieve an outright win. So maybe this shouldn't be a restriction, but instead an option for a more lively version.

Btw, there is already a piece called a 'Wizard' in a quasi-10x10 chess variant (with 4 extra corners added diagonally to each corner of a 10x10 chess board), invented by a Canadian. Maybe there is a 'Wizard' piece in other variants as well, although I don't know if there may be any patent restrictions on the name of 1 or more such fairy chess pieces.

Names cannot be patented. They can be trademarked, but no trademark office would allow a trademark to be applied to a name of a game piece such that no other game could use that name for a piece. The name of the game itself could be trademarked with some unique name, provided the name is not a generic term. For example, you couldn't name your game "Blue" and trademark that. I think the term "Wizard" would come into that restriction.

[edit: As an aside, I personally don't care that much if a variant develops great popularity only in a relatively short period of time (i.e. in less than decades, if not centuries [though I'd prefer to be alive to know about it]), so long as I have at least some opponents available locally (or at least in cities in my part of the world). In my altruistic spirit, I'm not too interested in making a profit from the creation of a chess variant that's eventually successfully spead far and wide, though in my competitive spirit, I would feel less indifferent competing in a cash prize event based on it - hope that doesn't seem too inconsistent. However, I can see that with the internet, if something isn't popular quickly these days, it possibly/likely may not ever become popular.]

I just read yesterday about the game app called "Flapping Birds". It is very basic and has very simple graphics. It was authored by someone in Vietnam, who did not expect anyone would even like it. To his surprise and apparent horror, it went viral around the globe, and he just pulled it out of the app store, saying only "I can't take it any more" without any further explanation. So it is no longer available, and devices that have it already installed are selling on eBay for as much as $15,000!!! Holy Cabbagepatch Doll, Batman!

Apparently no one knows why it went viral. There is no unique feature anyone can point to that made people crazy for it. It just happened. So who knows, maybe a 10 x 10 chess variant with 30 pieces per side can go viral after all.

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

...
A great example of how a variant can be just too overwhelming is Seirawan Chess, otherwise known as S-Chess. As you probably know, S-Chess brought 2 new piece types into a regular 8 x 8 chess board: one type combines Rook and Knight, and the other combines Bishop and Knight. These new pieces come onto the board only AFTER other pieces have vacated their start squares.

Although many people did take to this variant, it has never really caught on in a big way. The reason IMO is that these two new pieces simply have too many possible moves, making it almost impossible to envision strategy or even tactics. And on your 10 x 10 board with 6 extra pieces, wow, it would take centuries for any kind of strategy to develop.

Plus, it should be noted you're adding 2 new pieces for each player that are EACH more powerful than the Queen. Tactics are going to rule the day, and if super-GMs are missing simple winning moves now, who on Earth is going to master tactics in this game?

But I see that you have envisioned three combination pieces that I am a big fan of: Bishop and King, Knight and King, and Rook and King. These combinations are very much easier to visualize when calculating moves over the board.

So if you take these 3 pieces, and introduce them just as S-Chess does by placing them on an 8 x 8 board after moving an original piece from its start square, then I think there is real potential for mass acceptance there.

My own Seirawan Chess-like variant actually does away with the Rook-and-King combination piece. So each player has 2 pieces to bring onto the 8 x 8 board: the Archbishop (moves like Bishop and King) and the Champion (moves like Knight and King). Note how this naming is in harmony with the names of the existing pieces. The Archbishop is simply a more powerful Bishop. The Champion is the most powerful Knight. There is one of each, and pawns cannot promote to either of them. Neither is more powerful than the Queen. And as you noted for your pieces, the King-move capability does NOT include castling.

Also, to make these pieces, you don't need whole new physical pieces. The Archbishop can be a Bishop with it's top painted gold. The Champion can be a Knight with a red cross or shield painted on its flanks.

(My name for this variant is Full Court Chess, because these new pieces fill out the Royal Court... well, not quite, a Jester is still needed!)
...

Paul, I thought about your above comment in boldface a bit more, and it hit me this morning that Full Court Chess likely wouldn't be too much simpler than Seirawan Chess (S-Chess). That's based partly on Rueben Fine's observation (on some page I've forgotten, in Basic Chess Endings), that a king has an attacking/defending value of 4 pawns (in the endgame, it comes out of hiding), given that a standard chess minor piece has a material/attacking/defending value of 3 pawns, and a rook has a value of 5 pawns, as was thought back in Rueben Fine's day anyway.

That observation would reinforce my feeling that a piece that combines N+K (or, possibly slightly less so, B+K) powers (except for castling, naturally) would be perhaps only moderately less strong a piece (all other things balancing out) as one that combines B+R powers (i.e. a Q), by my estimation. A B+K (or, slightly less so, N+K) powers piece would be only moderately less strong than a piece that combines N+R powers, by my estimation. This is especially since such N+K or B+K powers pieces would not have to be prevented by the rules from being 'put in check', like the normal K by itself is.

Similarly, a piece that combines B+K (or, perhaps slightly less so, N+K) powers would be at least almost as strong a piece as one that combines N+B powers, again by my estimation. Thus, I am not at all sure Full Court Chess would seem much less overwhelming (at least to some) than S-Chess (although the restriction of Full Court Chess on dropping the two new fairy chess pieces only onto the home squares of the K and Q of an otherwise normal chess set may help a little, if it doesn't hurt the game's value in some way that S-Chess doesn't).

[edit: my estimates of these fairy pieces' relative values are based primarily on the number of squares each type of piece would control, especially from a central square on an empty board, although a piece's effectiveness in delivering mate (on its own or with little support) is an example of another factor that I took into account.]

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

There are many versions of pool / billiards in which one player gets to continue playing shots as long as s/he manages to sink one or more balls of a particular type (solid, stripe, certain numbers). This does not keep players from wanting to play these versions.
...
One of my double-move restrictions was that a player may not make 2 or more double-moves consecutively, with the idea of preventing a player from securing an initial advantage with the game's first double-move and then forcing that advantage all the way to mate using all their double-moves consecutively. But there is an allure to that possibility, in that it enables a go-for-broke mode of play. And of course, the opponent could reply with his / her own consecutive double-moves, and might even spare one or two for a possible endgame if the first player fails to achieve an outright win. So maybe this shouldn't be a restriction, but instead an option for a more lively version.
...

Yes, a double-move (besides possibly limited 'drops') is an example of a 'limited resource element' that intrigues me. It could be applied to chess to make it a new variant, or to a variant that possibly has other new rules/pieces/board(s) as well. However, having consecutive double-moves sounds a bit tricky to do feasibly, and it may be even less attractive (at least initially) for traditionalists. I can't clearly see why not to have players alternate having the option of making double-moves only one at time, kind of like a doubling cube is used in Backgammon (except stakes are not doubled, but rather 2 moves in a row are made [with restrictions, like you've suggested]). If consecutive double-moves are allowed, I can guess that at least some people may prefer Progression Chess, perhaps as an arguably 'cleaner' or simpler variant.

Btw, I edited my previous post somewhat extensively, concerning my estimates for the comparitive values of certain types of fairy chess pieces mentioned there, for those who haven't noticed (an example of the consequences of what can happen if you go on chesstalk in the morning, especially without enough sleep).

[Paul Bonham]

Re: Variants and Heterodox Chess Problem thread

Paul, I thought about your above comment in boldface a bit more, and it hit me this morning that Full Court Chess likely wouldn't be too much simpler than Seirawan Chess (S-Chess). That's based partly on Rueben Fine's observation (on some page I've forgotten, in Basic Chess Endings), that a king has an attacking/defending value of 4 pawns (in the endgame, it comes out of hiding), given that a standard chess minor piece has a material/attacking/defending value of 3 pawns, and a rook has a value of 5 pawns, as was thought back in Rueben Fine's day anyway.

That observation would reinforce my feeling that a piece that combines N K (or, possibly slightly less so, B K) powers (except for castling, naturally) would be perhaps only moderately less strong a piece (all other things balancing out) as one that combines B R powers (i.e. a Q), by my estimation. A B K (or, slightly less so, N K) powers piece would be only moderately less strong than a piece that combines N R powers, by my estimation. This is especially since such N K or B K powers pieces would not have to be prevented by the rules from being 'put in check', like the normal K by itself is.

Similarly, a piece that combines B K (or, perhaps slightly less so, N K) powers would be at least almost as strong a piece as one that combines N B powers, again by my estimation. Thus, I am not at all sure Full Court Chess would seem much less overwhelming (at least to some) than S-Chess (although the restriction of Full Court Chess on dropping the two new fairy chess pieces only onto the home squares of the K and Q of an otherwise normal chess set may help a little, if it doesn't hurt the game's value in some way that S-Chess doesn't).

[edit: my estimates of these fairy pieces' relative values are based primarily on the number of squares each type of piece would control, especially from a central square on an empty board, although a piece's effectiveness in delivering mate (on its own or with little support) is an example of another factor that I took into account.]

I can't argue against your points because it's all quite unknown. But my general thinking was like this: if you take a Bishop and add the ability to move like a King, you are basically adding only 4 more squares for it to move to, all of them right next to the current square. Whereas if you take a Bishop and add a Knight's moves, that is potentially 8 more squares and none of them right next to the current square. So immediately, it seems you have added mucher greater complexity because remember: you're not just looking 1 ply ahead. You're trying to look several plies ahead. King moves are easily visualized several plies ahead. Knight moves: not so much! :)

Ditto for Knight and King versus Knight and Rook.

So I think when it comes to visualizing several plies ahead, S-Chess overdid it. Maybe some super-geniuses can handle it, but most of us just look at an S-Chess middlegame position with all the extra pieces on the board and say, "I think I'll go on Youtube and watch the Bindi Cheng twerking channel!" ;)

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

Here's an example of a recently developed computer-resistant chess variant that's unattractive to me personally, because it involves sometimes choosing to switch sides with the opponent(!) under certain conditions, if one wishes (otherwise, I suppose it is like standard chess):

http://en.chessbase.com/post/a-new-c...hess-variant/2

[edit: Here's a link to an intriguing, highly complex game, played on an 8x8 board (and which could use/substitute chess pieces for it's pieces), also mentioned in the above link. It has simple rules, but only invented in 2002 and is waiting for computers to master still:

http://en.wikipedia.org/wiki/Arimaa

]

[edit: here's a link to another recently developed computer-resistant variant that doesn't exactly appeal to me personally, at least at first glance (edit: correction made here) :

http://en.chessbase.com/post/ken-reg...dem-pawn-chess

]

It would be interesting if there was ever a serious attempt made to compare any number of chess variants (besides standard chess), and rank them. Perhaps ideally the 'judges' might include any number of strong players. Over the years any number of strong players have 'endorsed' this or that variant, possibly without attempting to rank them in relation to other forms of chess. A poll of chesstalk viewers was made long ago, and it included standard chess and some variants that might be popular with viewers. Standard chess was voted most popular, with Double Chess a close second. A distant third was Chess960, which was half as popular as standard chess (the fourth place variant choice was pretty distant in turn from Chess960, in terms of votes, in this 10-option multiple choice poll):

http://www.chesstalk.info/forum/show...ighlight=chess

[edit: despite my concerns over possible 'cheating' in Double Chess expressed in this old chesstalk thread, I would nowadays regard these as negligible compared to the possiblity of computer-assisted cheating in standard chess (although I am still hoping this will not be as big a threat to the game as I fear, Mr. Ivanov notwithstanding).]

Here's wikipedia's entry for Bughouse (aka Double Chess), which is described as popular (worldwide?) - as I wrote in an earlier post, my main beefs with it are that it is best played by 4 players, not 2, and the clocks are often a decisive factor - otherwise, I think it is a fun game, which I can almost take seriously:

http://en.wikipedia.org/wiki/Bughouse_chess

[edit: one other possible problem with Double Chess is that its 'basic' rules have variants to them, at least at times depending on the part of the world the game is played in. Note that wikipedia's Double Chess rules (the ones that are without variants being offered) state that even exact moves can be suggested to one's partner, which I had thought being allowed depended on local rules for the game.]

Finally, here's wikipedia's main entry for chess variants:

http://en.wikipedia.org/wiki/Chess_variant

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

I can't argue against your points because it's all quite unknown. But my general thinking was like this: if you take a Bishop and add the ability to move like a King, you are basically adding only 4 more squares for it to move to, all of them right next to the current square. Whereas if you take a Bishop and add a Knight's moves, that is potentially 8 more squares and none of them right next to the current square. So immediately, it seems you have added mucher greater complexity because remember: you're not just looking 1 ply ahead. You're trying to look several plies ahead. King moves are easily visualized several plies ahead. Knight moves: not so much! :)

Ditto for Knight and King versus Knight and Rook.

So I think when it comes to visualizing several plies ahead, S-Chess overdid it...

On the whole I think I agree with this reasoning, but also by this reasoning it may well be better to use a R K powers piece, rather than a N K powers piece, in your Full Court Chess variant, i.e. because, as you basically say, a N alone can be a hard piece to visualize where it will influence a few moves in advance.

It may be a coincidence, but in Shogi there can be a B K powers piece ('Horse') AND a R K powers piece ('Dragon'), but there is no N K powers piece (and/though Shogi 'knights' have less legal moves available generally than chess knights).

The point of my post that you quoted is that even B K and N K powers pieces are powerful pieces to add to the chess army, and that was one criticism of Capablanca Chess (a 10-file by 8-rank board variant), i.e. that ordinary minor pieces become less significant in light of all those more powerful pieces on the board. This is a somewhat similar criticism to the one you made of my Sac Chess 10x10 variant (though like you also wrote, who knows what will become viral - there have been way more views of each of my 4Chess four dimensional chess variant chesstalk/CFC blogs than each of my Sac Chess 10x10 variant blogs [!]).


[edit: strangely, "Plus sign" symbols are no longer showing up (in my posts, at least). Maybe has something to do with chesstalk being down recently??]

[Kenneth Regan]

Re: Variants and Heterodox Chess Problem thread

[edit: here's a link to another recently developed computer-resistant variant that doesn't exactly appeal to me personally, at least at first glance (as one pawn on each side has special properties, which sort of spoils the pleasing near-symmetry of a given game's start position, of course only IMHO):

http://en.chessbase.com/post/ken-reg...dem-pawn-chess

]

Quick correction: not just one pawn on each side but every pawn is a tandem, so the start position is completely symmetrical in that regard.

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

I made a correction to my post that you quoted, with apologies to you, Kenneth.

All the same, I'd say your variant still wouldn't quite fully appeal to me, if it couldn't be made to somehow look nice on someone's coffee table, as a decorative set. That could help any variant better gain mass appeal, including also for any appearances it may have later on in popular culture, as in films.

[edit: the unaesthetic appearance of yoked (coupled) pawns is a superficial reason, I know, but potentially this factor could be badly underestimated. Aside from that, your 8x8 (48-piece!?) variant initially appeals to me about to the same degree as my own 10x10 60-piece Sac Chess variant (which I assume I haven't put as much thought into), but then I'm biased. My 4Chess variant is meant more for a computer screen than a tournament hall or living room. Your variant does seem rather computer-resistant, and I can guess that games with your variant wouldn't typically take a large number of moves to finish, and your tandem pawns would seem far less powerful than my new 10x10 Sac Chess variant piece-types would be.]

[edit: one solution to the aesthetic problem of yoked (coupled) pawns could be to design new sets that would allow the individual pawns (of relatively small size compared to the rest of the pieces) to be interlocked one on top of the other, and still be able to stand together on the same square, tower-like, when coupled. While this could work for plastic sets, there might be a problem for decorative sets with pieces made of harder material than plastic.]

[Paul Bonham]

Re: Variants and Heterodox Chess Problem thread

I made a correction to my post that you quoted, with apologies to you, Kenneth.

All the same, I'd say your variant still wouldn't quite fully appeal to me, if it couldn't be made to somehow look nice on someone's coffee table, as a decorative set. That could help any variant better gain mass appeal, including also for any appearances it may have later on in popular culture, as in films.

[edit: the unaesthetic appearance of yoked (coupled) pawns is a superficial reason, I know, but potentially this factor could be badly underestimated. Aside from that, your 8x8 (48-piece!?) variant initially appeals to me about to the same degree as my own 10x10 60-piece Sac Chess variant (which I assume I haven't put as much thought into), but then I'm biased. My 4Chess variant is meant more for a computer screen than a tournament hall or living room. Your variant does seem rather computer-resistant, and I can guess that games with your variant wouldn't typically take a large number of moves to finish, and your tandem pawns would seem far less powerful than my new 10x10 Sac Chess variant piece-types would be.]

[edit: one solution to the aesthetic problem of yoked (coupled) pawns could be to design new sets that would allow the individual pawns (of relatively small size compared to the rest of the pieces) to be interlocked one on top of the other, and still be able to stand together on the same square, tower-like, when coupled. While this could work for plastic sets, there might be a problem for decorative sets with pieces made of harder material than plastic.]

Why would the pawns have to be on top of one another? If two can fit side by side on a single square, line them up that way. There's no actual need to yoke them, that was just a suggestion and it might be better to just move them together if they are to remain coupled.

The more I think about this variant, the more intrigued I am. Ken, if you are reading this: what about allowing any single pawn that is on a square horizontally next to a square of another single pawn of the same color being allowed to move sideways to become a tandem?

One advantage of keeping a tandem coupled, especially in endgames, is the zugzwang considerations. In a standard chess position where it's bad for you to advance a pawn because it leaves a hole for a long-range piece to take advantage of, having that pawn be a tandem that can be decoupled allows making a move but still keeping a pawn on the original square.

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

Why would the pawns have to be on top of one another? If two can fit side by side on a single square, line them up that way. There's no actual need to yoke them, that was just a suggestion and it might be better to just move them together if they are to remain coupled.

The more I think about this variant, the more intrigued I am. Ken, if you are reading this: what about allowing any single pawn that is on a square horizontally next to a square of another single pawn of the same color being allowed to move sideways to become a tandem?

One advantage of keeping a tandem coupled, especially in endgames, is the zugzwang considerations. In a standard chess position where it's bad for you to advance a pawn because it leaves a hole for a long-range piece to take advantage of, having that pawn be a tandem that can be decoupled allows making a move but still keeping a pawn on the original square.

Having small pawns side by side (or back to back) on the same square as an alternative to yoking them was indeed mentioned in Ken's article, as I did notice [edit: I used "(coupled)" to include this alternative, right after "yoked", in my previous post, the meaning of which I suppose may not have been altogether clear]. That doesn't negate at all my point about it looking unaesthetic (either way).

In my sense of aesthetics, at least, interlocking pawns coupled one on top of the other would be preferable [edit: sadly, this means that existing standard chess sets, even plastic ones (I would think) would be unsuitable for this aesthetic purpose, although, even otherwise, pawns must be 'borrowed' from existing sets to be used with existing sets, even if a tandem pawns variant set is only to be a decorative set for a coffee table.]. Plus, pawns coupled vertically might kind of give extra meaning to Ken's optional 'Rocket move' as a decoupling move.

[edit: to repeat, aesthetics could wind up mattering a great deal to marketing, promoting or popularizing a variant.]

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

Apparently my old Throne Chess variant idea (e.g. see my chesstalk blog entries) is more 'out there' on the web than I thought. Don't know if someone invented the variant independently, but here's a link to a blog promoting it (personally I've just about given up on Throne Chess becoming popular, and it doesn't fully suit my desires for a variant nowadays because it isn't very computer-resistant):

http://thronemateabettergameofchess....-of-chess.html

[Tom O'Donnell]

Re: Variants and Heterodox Chess Problem thread

A chess option that I have never seen in print, but did play a few times, involves only one rule change: you can capture your own material, in the same way you can capture your opponent's. It leads to potentially sharper play as (for example) you no longer need to play h2-h4-h5 in the Yugoslav Dragon but can just play Rxh2. It isn't anti-computer, however.

[Nigel Hanrahan]

2014 British Chess Problem Ch.

John Nunn has a brief article at ChessBase in which he provides the bulk of the problems used in the British Problem Solving Championship(s). The problems, along with the solutions, include:

1. White to play and mate in 2;
2. White to play and win;
3. Helpmate in 5;
4. Selfmate in 4.

The Selfmate is an amusing concept. As Nunn puts it, "White is trying to commit suicide by forcing Black to mate him, while Black is doing everything in his power to avoid this."

Incidently, John Nunn, the author of the article, won the event.

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

A chess option that I have never seen in print, but did play a few times, involves only one rule change: you can capture your own material, in the same way you can capture your opponent's. It leads to potentially sharper play as (for example) you no longer need to play h2-h4-h5 in the Yugoslav Dragon but can just play Rxh2. It isn't anti-computer, however.

An idea that I've just thought of could possibly give rise to viable computer-resistant chess variants, though I don't know if this idea is at all sound or good (or been thought of before).

Namely, in such a variant (which for now might be called Quiet 2-move chess, at least if played on a standard 8x8 chess set), a player can make 2 'quiet' moves in a turn (or optionally, or out of legal necessity, just 1 'quiet' move). That would be provided neither move is a checkmate, a check or a capture, nor if the first of the moves (if by a pawn) would deny the opponent a normal 'en passant' capture possibility. A player would otherwise be only allowed to move one move in a turn instead. That would be, if he gave mate or a check, made a capture, or made just a double-step pawn advance that would then be final, due to having to allow an 'en passant' capture possibility. Note that he could not move a pawn 'one step twice in a row' and then claim that he's not allowing an 'en passant' move in reply. [edit: Stalemate would still be a draw. Otherwise, a complete turn by a player must change the position in some way. One concern I have is that some basic endgames might become draws.]

I think this might greatly expand the number of legal possibilities per half-turn, as compared to standard chess. Using a standard 8x8 board chess set, this would not allow such a variant to, in an average turn by one player, get near the approx. 17000 possibilities per turn by one player that arise on average in Arimaa, but if a 10x10 board chess variant set, with 30 pieces per side, was used, say as in my 10x10 variant that I posted on page 2 of this thread, then the number of possibilities increases to much closer to 100,000 per turn by one player on average, I'd estimate (with a 12x12 board chess variant set, with 48 pieces per side, the branching factor would be even more impressive). One question is whether the high number of queen-like pieces in my 10x10 variant would inevitably spoil any sort of computer-resistance for it, due to its complexity being possibly favourable for a machine, even with the 1-move/turn restriction on capturing (etc.) moves.

[Kevin Pacey]

Re: Variants and Heterodox Chess Problem thread

Update:

I put 4Chess (& changes to start position on my chesstalk blog) & 'Sac Chess' on my blog on the CFC Board year ago. 'Four dimensional chess' had 1230 views, & '10x10 Chess Variants' blog entry (with 'Sac Chess') had 15772. Throne Chess (mate or K to K8 wins) had 3983 views on my CFC blog (close to 'Game of Thrones' when Googled, so noticable [though not to chess players so much], like 10x10 chess variants title).

I blogged all 3 variants in Feb 2014. Maybe significant interest in 10x10 variants, beyond curiousity. I've included Sac Chess blog's text below - in a noted edit I gave a variant on 'Sac Chess' replacing each side's 2 Amazons with 2 pieces which each are not clearly more powerful than a standard chess queen, to take account part of Paul's objection to Amazons in 'Sac Chess' in case other viewers might feel the same way.

Hi Kevin,

I think any 10 x 10 variant is just too overwhelming for mass acceptance... it should be noted you're adding 2 new pieces for each player that are EACH more powerful than the Queen. Tactics are going to rule the day, and if super-GMs are missing simple winning moves now, who on Earth is going to master tactics in this game?
...

From my CFC Board blog:

10x10 Chess Variants

Based on a chesstalk forum post of mine:

I thought I'd show an idea for a 10x10 chess variant I've been playing around with, using chesstalk's table coding capability to make a kind of diagram for the start position. My goal was to have a variant perhaps not too wildly different from standard chess, yet possibly capable of being computer-resistant as far as the number of legal moves available in a position typically might go. Note that in comparison to the popular 'Grand Chess' 10x10 variant the start position of my variant is more orderly, given that there are no empty squares on either side's first or second rank (a bonus is that in a way I retained the starting positions for the standard chess pieces, a memory aid to those who play standard chess). Also, note Fool's mate and a kind of Scholar's mate are still possible, like in standard chess (and in the same number of moves):

Col a Col b Col c Col d Col e Col f Col g Col h Col i Col j     Col xx

 [C]  :[A]:  [S]  :[Z]:  [M]  :[M]:  [Z]  :[S]:  [A]  :[C]:       10

:[J]:  [R]  :[N]:  [B]  :[Q]:  [K]  :[B]:  [N]  :[R]:  [J]         9

 [P]  :[P]:  [P]  :[P]:  [P]  :[P]:  [P]  :[P]:  [P]  :[P]:        8

:::::       :::::       :::::       :::::       :::::              7

      :::::       :::::       :::::       :::::       :::::        6

:::::       :::::       :::::       :::::       :::::              5

      :::::       :::::       :::::       :::::       :::::        4

:(P):  (P)  :(P):  (P)  :(P):  (P)  :(P):  (P)  :(P):  (P)         3

 (J)  :(R):  (N)  :(B):  (Q)  :(K):  (B)  :(N):  (R)  :(J):        2

:(C):  (A)  :(S):  (Z)  :(M):  (M)  :(Z):  (S)  :(A):  (C)         1

In this variant 6 new types of pieces than in standard chess are introduced besides the standard 6 types:
Z = Amazon (moves like N or Q), a standard fairy chess piece idea;
C = Chancellor (moves like N or R [without castling]), a standard fairy chess piece made famous by Capablanca Chess;
A = Archbishop (moves like N or B), a standard fairy chess piece made famous by Capablanca Chess;
S = Sailor (moves like R or K [without castling]), a piece from Shogi (promoted Rook, or 'Dragon', in that game);
M = Missionary (moves like B or K [without castling]), a piece from Shogi (promoted Bishop, or 'Horse', in that game);
J = Judge (moves like N or K [without castling]), my idea possibly, as inspired by the Shogi piece types mentioned.

Castling may occur on the second rank between the king and either rook, with same conditions as in standard chess. Pawns act standardly too, the only difference being that while they still promote on the last rank, any of the new types of pieces may be selected, besides piece types allowed in standard chess. Stalemate is a draw, like in standard chess.

An example game that might delight a beginner is one version of a Fool's mate: 1.Pg3-g5 Pf8-f7 2.Ph3-h5 Qe9-i5 mate. Then there is one version of Scholar's mate: 1.Pf3-f5 Pf8-f6 2.Bg2-d5 Nc9-d7 3.Qe2-g4 Nd7-e5 4.Qg4xg8 mate.

A possible drawback to this variant of mine (maybe let's call it 'Sac Chess'!? - note the initials of the last three pieces on White's 1st rank :D) is that if one avoids blundering early, such as above, a typical game might be lengthy given that there's so many extra pieces and squares compared to standard chess, and a king is typically going to be well defended for a while, I'd guess. [edit: However, note that advocates of the oriental game of Go at times like to point out that, in terms of number of moves typical for a whole game to be played, standard chess is a battle (about 40 moves per side on average), while Go is a war (usually over 100 moves per side).] Testing is needed, if there's interest.

[edit: for those who think Sac Chess might prove too complicated to attain any popularity, below is a link showing the even more complex Middle Shogi variant (on standard 9x9 Shogi, or Japanese chess), which has a certain degree of popularity in Japan, at least.]

http://en.wikipedia.org/wiki/Chu_shogi

[edit: In Sac Chess there can be a point to underpromoting to any other piece than an Amazon, except in some cases the only point could be to deliver mate sooner (or making the most valuable underpromoted piece), based on positions I've imagined so far - including for promoting to just a B or N. Also, smothered, or even back rank, mates are conceivable, though they would be rarer than in standard chess (Grand Chess would have a similar arguable drawback).]

For comparison, here's a link describing 'Grand Chess':

http://en.wikipedia.org/wiki/Grand_chess

Note that 10x10 boards are already well in use for 'International Checkers' purposes, I gather.

[edit: a name for my variant many might prefer instead of 'Sac Chess' could possibly be 'International Chess', if that name isn't already taken.]

[edit: a possible variation on 'Sac Chess', for those who don't like Amazons being clearly superior to normal Queens (in terms of legal moves relatively possible, anyway), is to replace all four Amazons as follows: (1) on the 'd' file use a new type of piece for each side in place of an Amazon in the start position. This new type of piece of mine combines the powers of R, N and K (excluding castling), and I call it a 'Ship' or 'H'. (2) Similarly, replace the Amazons on the 'g' file with a new type of piece that combines the powers of B, N and K (excluding castling). This new type of piece of mine is called a 'Freemason' or 'F'. Note that in the new start position, like for standard chess, more versions of Scholar's mate would be possible than in 'Sac Chess'. I'd call this variant 'Cash Chess'. :) I prefer Amazons though, with more symmetry at the start and one less piece type]

Here's a sample Sac Chess opening possibility, besides the Fool's mate and Scholar's mate given earlier. It starts, in a way, like the Italian, Two Knights Defence, Wilkes Barre variation in standard chess:

1.Pf3-f5 Pf8-f6 2.Nh2-g4 Nc9-d7 3.Bg2-d5 Nh9-g7 4.Ng4-h6 Bg9-d6 5.Bxg8+ Ai10xg8 6.Nh6xg8 Zg10xg8.

In my estimation Black has adequate compensation for his archbishop based on his lead in development. Here's the position after Black's sixth move:

Col a Col b Col c Col d Col e Col f Col g Col h Col i Col j     Col xx

 [C]  :[A]:  [S]  :[Z]:  [M]  :[M]:       :[S]:       :[C]:       10

:[J]:  [R]  :::::  [B]  :[Q]:  [K]  :::::       :[R]:  [J]         9

 [P]  :[P]:  [P]  :[P]:  [P]  :::::  [Z]  :[P]:  [P]  :[P]:        8

:::::       :::::  [N]  :::::       :[N]:       :::::              7

      :::::       :[B]:       :[P]:       :::::       :::::        6

:::::       :::::       :::::  (P)  :::::       :::::              5

      :::::       :::::       :::::       :::::       :::::        4

:(P):  (P)  :(P):  (P)  :(P):       :(P):  (P)  :(P):  (P)         3

 (J)  :(R):  (N)  :(B):  (Q)  :(K):       :::::  (R)  :(J):        2

:(C):  (A)  :(S):  (Z)  :(M):  (M)  :(Z):  (S)  :(A):  (C)         1

Now best may be 7.Pe3-e4 Pe8-e6 8.Pi3-i4 (to stop ...Bd9-h5). Black can win back his pawn, but White can castle.

Here's my tentative estimates for the relative values of Sac Chess pieces:

P=1, N=3, B=3.5, R=5.5, Q=10, almost as per standard chess. I believe I once read in a book by a Grandmaster that a standard chess K has a fighting value of 4, though it cannot be exchanged naturally. I took that into account in some of my estimates for the new pieces in Sac Chess that follow:
Z=14 (just as Q=R+B+P in value, Z=Q+N+P in value)
C=9.5 (just as Q=R+B+P in value, C=R+N+P in value)
A=7.5 (just as Q=R+B+P in value, A=N+B+P in value)
S=8 (only half a king's moves are added to a rook to make a sailor, and since Q=R+B+P in value, so S=R+(K/2-P/2)+P in value)
M=6 (only half a king's moves are added to a bishop to make a missionary, and since Q=R+B+P in value, so M=B+(K/2-P/2)+P in value)
J=8 (just as Q=R+B+P in value, J=N+K+P in value).

For those wishing to replace Amazons with the two other pieces I suggested earlier, I estimate their relative value as follows:

H (Ship) =12 (just as Q=R+B+P in value, H=S+N+P in value)
F (Freemason) =10 (only half a king's moves are added to an archbishop to make a freemason, and since Q=R+B+P in value, so F=A+(K/2-P/2)+P in value).

While I estimate a ship would be worth more relative to a queen, at least a queen's powers are not duplicated (and then some) by a ship. I should also mention I've imagined cases where it's advantageous in some way to promote to a freemason (or ship).