Creating chess variants on the spot

[Ovyron]

I've been thinking about inventing some chess variants recently, though sometimes it's surprisingly difficult to come up with something that doesn't already exist...

Some ideas:

Teleporting King - The King has a special move "teleport" that can be used once per game, to warp to any unnocupied square of the board that is not attacked (any square that would be legal if the king was adjacent to it.)

When to do it could become critical, as I imagine waiting and waiting instead of using it prematurely would be advantageous, but too late and being able to teleport doesn't change the outcome of the game and it's a wasted ability.

Special Abilities - Every piece on the board comes packed with a special move that it can use once per game. The ability may not be used if using it would capture a piece:

Queen - Can move like a Knight once per game
Rook - Can move like a Bishop once per game
Knight - Can move to any square protected by a Knight once per game (ability lost if that Knight is captured)
Pawns - Only if a pawn hasn't "jumped" 2 squares from its starting position, it may "jump" once at any point in the game. Capturing "en passant" works against such pawns. Note that pawns that never "jumped" in the entire game and promoted upgrade their ability to the promoted piece, usually a Queen that can jump like a Knight once.
King - Can Move like a Queen once per game.

Drop Chess - Game starts with an empty board, White starts the game dropping their King anywhere on the board, then black drops their King wherever it would be legal for the King to be.

Afterwards, each side can either make a legal move, or drop a piece/pawn where it would be legal for the piece to be, on an empty square. Pawns can only be dropped in rows 2-7.

Drop Crazyhouse - Like Drop Chess, but pieces you capture can be dropped later like in crazyhouse.

This variant can already be played at somewhere like Lichess, if you play Crazyhouse, then allow each side to capture all the material of the other side, leave the kings in the places you want to start the game in, and the first 2 dropped pieces so the game isn't claimed as a draw by the server.

StrateChess - Players, secretly, before the game starts, assign a rank to each of their pieces/pawns, except the King. These ranks go from 1 to 9, and two special ranks "S" for "Spy", and "B" for "Bomb", with ranks 5 to 9 and B being repeated.

Then, whenever a piece is captured, the players reveal the ranks for the attacking and defending pieces. If the rank of the attacking piece is of a lower number, play continues as normal. If it's of a higher number, the attacking piece loses and is removed instead.

The "Spy" loses against every other rank, except rank 1 (so rank 1 loses when trying to capture the Spy, or when the Spy captures it.)

The "Bomb" wins against any rank, except rank 8 (so rank B loses when trying to capture the 8, or when the 8 captures it.). However, once a piece with rank "B" has been found, it's illegal for it to move all game.

Other than this, the King doesn't care about the other pieces' ranks, and moves normally, with other pieces being able to check and checkmate it regardless of rank (except for immobile pieces with rank "B", which may no longer put the king in check.)

The game is about investigating the ranks of the opponent's pieces as they have to reveal them to you on captures, to develop a strategy. I'd imagine there would be interest in uncovering the opponent's Spy, since, once it's dead, your pieces of better rank can scout for Bombs so that once they're gone your piece of rank 1 becomes unstoppable.

[hgm]

The Teleporting King is probably not a good idea. It sort of defeats any sacrificial mate attack, as the opponent would simply teleport away, leaving you in a lost position. (As you say, the value of the teleport you have left shrinks to zero anyway when he trades down to an elementary won end-game.) This just seems to empoverish the game. Tai Shogi suffers from a similar problem: there the royal piece is an Emperor, which can always teleport, and forces you to play the game until no other material is left. (And that in a game where each player starts with 177 pieces. Truly awful!)

This is also my reservation against the variant described by Uri, where you win by completely annihilating your opponent. It seems to me that it would be excessively difficult to beat an opponent that avoids trading his Queen, as Queens are extremely difficult to catch. It basically becomes a Draughts variant, except that there already is a Queen in the start position. There exists a variant 'Extinction Chess', where the purpose is to eleminate one piece type. So you would win by capturing the King or Queen, both Rooks, Bishops or Knights, or all eight Pawns. That at least is feasible.

StrateChess seems more a Stratego variant than a Chess variant.

[Henk]

When computers are able to solve chess within a few hours the future will be that human players will participate in a chess tournament where before each game they get the rules of the chess variation they should play that are invented by computers.

[Ovyron]

The Teleporting King is probably not a good idea. It sort of defeats any sacrificial mate attack, as the opponent would simply teleport away, leaving you in a lost position.

Haha! Yeah, the variant was actually inspired by such attacks by stronger opponents, making me think "oh, how I wish I was able to just teleport my King to the other side of the board, leaving all those attack pieces hanging!"

I wonder if the variant can be saved, for instance:

Players start with a Teleport Token on their hand, at any point, they may use it to teleport any piece to any other empty space of the board, once per game. A pawn could use it to advance two squares without being captured "en passant" next turn, but may not use it to teleport directly to the end of the board and promote.

However, if you use your token to teleport your king, you must hand it to your opponent, so now they can teleport their pieces.

This way, you can launch an attack on the opponent's king, and if it runs away, you can still chase him down by teleporting two of your pieces to its new location. We could make it so that, if you have more than one token, you can use both on the same turn, so it's easier to mate it on its new location, or whatever is necessary so that sacrifices to mate the king still work.

StrateChess seems more a Stratego variant than a Chess variant.

Is there a way to apply such concepts to chess so that it still feels like a Chess variant? It seems the main problem is how the pieces move loses relevance when their rank is the most important thing regarding captures.

Anyway, this is another old one that I started to implement in a Game Maker program:

Hit Point Chess - When a piece is captured, it returns to the owner's hand, and it can be dropped back on a later move, in an empty space of the board (pawns limited to 2-7 rows.)

Every time it happens, 1 Hit Point is taken away from the piece, and once it hits 0, the piece doesn't return to the owner's hand. The King is checkmated as in normal chess.

Chess is a subset of Hit Point Chess, for a variant where all pieces start with 1 Hit Point.

With 2 Hit Points, capturing a piece of the opponent allows it to be dropped anywhere on the board, so it may be a liability.

There can also be variants where different pieces start with different Hitpoints, so, say, Pawns have 8 Hit Points, so they just keep coming back to life, while Bishops and Knights have 5, Rooks have 3, but the Queen has 1. This would be like "Reinforcement Chess", where the sides have extra material off board, but it may only be used when existing material is captured.

There can also be a variant with infinite Hit Points, that looks like a reverse Crazyhouse where captured pieces are awarded to the wrong player, though I fear something like this leads to repetitions of positions, where the best move is just keeping capturing the same pieces and dropping them on the same squares.

[Greg Strong]

There are thousands of chess variants already but most are not very good. It is very difficult to come up with an original variant that is worth playing. May I respectfully suggest that the first step would be start playing existing variants so you learn what works and what doesn't. I'd recommend signing up at the Chess Variant Pages and striking up some correspondence games on Game Courier.

[Evert]

Your "drop chess" rules are under-specified, I think. Am I allowed to drop pieces with check? If so, white can probably just spam check-drop black from the second move (winning tempo) and win easily. Dropping pawns one square from promotion is probably also not such a great idea.

Perhaps it's worth looking at Sittuyin, I think that has very sensible opening/drop rules. Promotion rules, not so much, but the drop aspect of the game is great.

[hgm]

There already exist variants where you start with all pieces in hand. E.g. Kahn Chess. This also has the extra winning condition of a King reaching last rank. (But there is a limitation how close to that rank you can drop it.)

In Raindrop Chess you must draw cards that specify what piece you can drop.

[Ovyron]

May I respectfully suggest that the first step would be start playing existing variants so you learn what works and what doesn't.

I have played chess variants for the last 24 years (I was developing Hit Points Chess in 2007), that's a main reason for my interest in trying to invent new things for them. For some reason I was never a fan of strange fairy piece with odd movements, they don't feel like chess at all, so I've been trying to come up with things that use the pieces I already love, because I didn't like Gothic chess's archbishops and chancellors.

I was a great fan of Zillions of Games, it had a powerful, yet simple code, that would allow you to create any kind of variant that you liked, my very first attempts were "Knightmate" (the king moves like a knight, and the knights are replaced by non-royal kings) and "Pawnmate" (the king is replaced by a pawn, that may jump from the first rank to the 4th rank, and all pawns were replaced by non-royal kings that may promote), and one could test them from the get-go as Zillions had an AI that could play any variant that you implemented.

It's overwhelming to see that any variant that one implements will sink in the big sea of variants that already exist, though, I wonder if the next Atomic Chess (very popular variant, played by thousands of people daily) can be created.

[Ovyron]

There already exist variants where you start with all pieces in hand. E.g. Kahn Chess.

Okay, thanks, where can I find more info about Kahn Chess? Google only shows 8 results for variant, and none seem to match it.

[Greg Strong]

May I respectfully suggest that the first step would be start playing existing variants so you learn what works and what doesn't.

I have played chess variants for the last 24 years (I was developing Hit Points Chess in 2007), that's a main reason for my interest in trying to invent new things for them.

Sorry, didn't realize. I tend to assume that chess variant fans are active on the CVP, but of course not all are.

I was a great fan of Zillions of Games, it had a powerful, yet simple code, that would allow you to create any kind of variant that you liked

Indeed, it was a shame that Zillions was completely abandoned. That's where I started too, and its short-comings are what inspired me to make ChessV. ChessV does have a scripting language but it's in very early stages of development so it is pretty limited (you can make new pieces and combine pieces and existing rules, but you cannot use it to create new rules.) If you can work in C#, though, you can add your own variants fairly easily and you'll have a strong AI opponent - much stronger than ZoG ever was. If you download the source code, the zip contains a fairly detailed document describing how ChessV is put together, and how variants are programmed with several examples.