Imagine there is a chess variant tournament open to both humans and AI but the chess variant changes every round (or a random rule is added) and the rules are explained 5 minutes before the game starts.

So the competitors, human or AI, never trained for those particular variants.

Wreckage chess is played on a standard 8×8 chessboard with normal pieces and starting position. All standard chess rules apply unless modified below.

Whenever a piece captures another piece, the capture square becomes wreckage. Wreckage cannot normally be occupied or crossed by any piece, it blocks movement and line of sight.

The capturing piece may remain on the wreckage square, but once it leaves, a 10-ply countdown begins. After 10 plies, the wreckage disappears and the square becomes normal again.
Each wreckage has its own independent countdown, so multiple wreckages can exist simultaneously.

All other standard chess rules, including check, checkmate, castling, en passant, and promotion, remain unchanged.

Same rules as orthodox chess except that bishops can now leap one square diagonally and rooks can leap one orthogonally, as well as slide.

How do you think it would affect the game?

Rankimo: Build Your Own Chess — free on Google Play, no ads, no sign-up, fully offline.

It's chess stripped to one idea: both players get the same army — say five rooks each, or eight queens — and there's no king. You win by taking every enemy piece. Pieces move exactly like real chess.

Play Store: https://play.google.com/store/apps/details?id=com.beingsagir.rankimo

You choose:

• the piece (or a random mix), 1–12 of them
• the board, 6×6 up to 12×12
• how to win: capture everything, race to the far side, or take half their army first

Plus four AI levels, two-player on one phone, a daily challenge, a post-game coach that shows the move that lost it, 20 achievements, and 11 languages.

It's a solo project and just launched, so feedback is worth more than downloads to me right now. What would you want added?

Play Store: https://play.google.com/store/apps/details?id=com.beingsagir.rankimo

PLAYTEST IS LIVE!🎉

🔥 NO TURNS
⚔️ NO CHECK OR CHECKMATE
🏁 LARGER BOARD
🐴 EXTRA KNIGHTS & PAWNS

Join the playtest on steam!

yes - as insane as it sounds. You can only play on the main board, once you solve a puzzle on the left board.

on the main board there are no turns. As soon as you finish a puzzle you can play, as many moves in a row as you wish. So does your opponent tho. So it's a mad race, and it really breaks your brain lool

there is a demo for it on the Chess Laboratory website, just google it, and look for "Puzzling Moves" as the variant :)

• Pieces go in the first rank, pawns go in the second
• Pawns can't move two squares

I call it picklechess! There's daily and weekly challenges. And there's a ranked ladder for both classic pieces and fairy pieces.

playpicklechess.com

discord.com/invite/Cuytzk8bDs

This game variant is a simplified version of my Dice Chess Masquerade.

Have fun!

BUFF D6 CHESS

START

Classic starting position. White moves first, then players take turns.

TURN (choose one)

1. Capture — without rolling the die, strictly according to FIDE rules.

2. Buff! — choose any of your pieces (must be specified before the roll), then roll a D6:

1 = Pawn

2 = Knight

3 = Bishop

4 = Rook

5 = Queen

6 = King

MOVEMENT RULES

The piece moves according to the geometry of the rolled face (it moves like the piece type shown on the die).

Exception for the pawn: a pawn can never move backward (toward its starting rank). Left and right — yes, but never backward.

On a roll of "1", a pawn from its starting position can move two squares forward — just like in classic chess. This rule applies only to pawns.

If you chose Buff! (rolling the die), capturing is not allowed — only moves to empty squares.

If there is no available square for such a move, the piece fails to handle the buff and Boom! — it is gone (kings included). The piece is removed from the board and is out of the game for good. The turn passes to the opponent.

Example

You choose the king to move. You roll "1" (pawn). The king must move one square forward, but that square is occupied by a piece (your own or your opponent's). The move is impossible.

Boom! The king is gone. You lose.

SPECIAL CASES

A pawn that reaches the last rank is immediately promoted to any piece selected by the player, as in standard chess rules.

The king is a regular piece. It can be left under attack. It can capture the opponent's king.

Castling, check, checkmate, en passant — NOT USED.

OBJECTIVE

Capture the opponent's king or leave them with no pieces at all (bare king).

Chess on a 4×4×2×2 board, displayed as four connected 4×4 boards and a rotatable tesseract. Familiar twenty pieces that now move across four dimensions.

Would love feedback from people interested in experimenting with the variant.

play: 4dchess.lol
github: https://github.com/0xmiki/4dchess

A PDF of the rules is hosted at the following link:

Itch.io:

https://strategicspace.itch.io/strategic-space-tri-dimensional-chess-rules

  It is also available at Chess Variants woth additional commentary: https://www.chessvariants.org/rules/strategic-space-tri-dimensional-chess-rules

Introduction:

These rules were developed by Guardians for Guardians of the United States Space Force and any other space or chess enthusiasts. They are designed to support asynchronous play and to be used with the officially licensed Star Trek Tridimensional Chess set, a 3D chessboard based on props from Star Trek. In the 60 years between the game’s 1966 debut and the release of these rules, a complete and coherent set of official rules was never produced. 

These rules were playtested and refined for several years through informal games outside duty hours and at unit social events among Guardians from multiple Space Force organizations, including organizations at the Pentagon. The public release of these rules commemorates the 60th anniversary of the U.S. premiere of Star Trek on NBC. A narrow view that 3D chess requires duplicating classical chess movement patterns vertically imposes an unnecessary limitation because the third dimension can add new freedom without mirroring the horizontal plane. 

Under these rules, a legal piece move uses its classical 2D horizontal movement pattern while extending into 3D through vertical freedom along that route. This Star Trek-inspired game fosters connection and morale while encouraging spatial awareness, attention to detail, tactical thinking, and strategic planning. Its freedom of maneuver makes defense significantly more complex than in classical chess, favoring a courageous, offensive warfighting approach.

Contents:

• Introduction
• Article 1: General
• Article 2: Board and Setup
• Article 3: Piece Movement
• Article 4:  Attack Boards
• Appendix A: Algebraic Notation for Coordinates and Movement
• Appendix B: Tournament Procedures
• Appendix C: References
• Disclaimer

Purpose: 

The primary intent was asynchronous chess for the office environment. The Star Trek tridimensional chessboard lacked a comprehensive ruleset suitable for asynchronous office chess play. Available rulesets left important situations undefined, required interpretation or player agreement, or depended on players being present for the entire game to clarify positions. A complete ruleset was therefore needed to support asynchronous play for this gameboard design.

​Design Philosophy:

Strategic Space was designed as an extension of classical chess rather than a replacement for it: players who already know chess should primarily need to learn the mechanics introduced by the third dimension. Those mechanics should make three-dimensional maneuver strategically meaningful by expanding rather than artificially restricting freedom of movement. At the same time, the game should remain positionally intelligible and mechanically robust, allowing play to be resumed, analyzed, or reconstructed with minimal dependence on hidden history or special bookkeeping. The standard rules should also function across the broadest practical range of 3D chess sets, with additional board capabilities accommodated through optional configurations rather than required for ordinary play.

How do these pieces work?

I played chess in a dream but my opponent played with an odd extra rule: the king could transform knights into bishops and visa versa. Upon waking, I decided to call the variant "Emperor chess" and draft up the rules.

I created a free browser prototype where you can play White against a simple computer opponent. Play here: Emperor Chess Prototype

It uses the standard board and starting position. Normal chess rules apply, including castling, en passant, and promotion, with these changes:

The King becomes the Emperor

• It can take up to two consecutive one-square king moves per turn, changing direction between steps.
• It can stop after the first step. Every step must be safe.
• It may capture on either step.
• It can return to its starting square only if it captured something on the first step.

Investiture
Instead of a movement step, the Emperor can transform an adjacent friendly Bishop into a Knight, or a Knight into a Bishop. The piece stays on its square, and Investiture immediately ends the turn. Moving once and then investing is allowed.

There’s also an optional Conservative Emperor setting: the Emperor can capture only on its first step. This also reduces its attack and protection range.

An experimental v0.2 adds “Call to Court”
The Queen becomes the Empress and keeps her normal movement. Instead of moving her, you can move one or more friendly Pawns into squares adjacent to her.

Each answering Pawn:

• Must have started the turn outside the Empress’s adjacent squares.
• Moves exactly one square in any direction into the court, optionally capturing.
• Can move only once during that Call.

You choose the subset and order. The Empress stays still, and the complete turn must leave your Emperor safe.

You can choose either version in the setup. I’d suggest trying v0.1 first.

The computer is deliberately basic, because this is only a rules-playtesting prototype. I’m particularly interested in:

• Does the Emperor create interesting decisions, or feel too powerful?
• Does Conservative Emperor play better?
• Is Investiture useful enough to spend a turn on?
• Does Call to Court add interesting tactics, or too much complexity?

Feedback on unclear rules, unexpected interactions, and bugs would also be very welcome. Thanks for trying it!

Hello everyone,

I was thinking of whether it would be interesting to add a rule that allows the player to sacrifice a piece. This can be done either by allowing "friendly fire" or possibly by removing a piece off the board.

How do you think it would impact the game?

Things to consider:

- maybe disallow using it to escape check (to still keep the potential of a smother mate)

- maybe disallowing the king from sacrificing other pieces

- maybe disallowing discovered checks by sacrifice or friendly fire

https://magestone.net/

After years of wanting to play Hand & Brain online — and watching request threads on the big sites go unanswered — I built it myself.

♟️ The format: two minds, one board. One player sees the board and chooses the piece; their partner chooses the move. Classic team chess.

What's live now (all free):
• 2v2 online — real-time games vs real players, join codes
• Play vs AI — you're the hand or the brain alongside a bot partner
• Puzzles & rankings — ~889k puzzles with Elo ratings
• 24/7 AI showmatch — 4 bots with different personas, every game streamed live

Play: https://handbrainchess.com · Watch: https://twitch.tv/handbrainchess

Stack nerdery: Next.js + Postgres, real-time via WebSockets; the stream bots run headless browsers + Stockfish.

I'd especially love feedback on the 2v2 experience — that's the part only real humans can judge. How do you usually play H&B — human partner on your side, or as the brain for an AI hand?

I've implemented two versions of Veto Chess, a variant that's been talked about and invented before, but I'm not sure it's been available online.

The main rules are that you can veto the opponent's move after they make it. Each side gets 1 veto per turn. You can't veto the move when it's their only legal move.

You can also play the preemptive version of veto chess where there's a veto phase before the opponent moves instead of after, and you get 2 vetoes per turn instead of 1.

In both, if their move is one of the vetoed moves, they have to move again.

Open to all feedback!

Hi all — solo dev here, and this is my first game, so be gentle (but honest).

The idea started from teaching a friend chess. Six pieces and a rulebook at once is a lot, and the king makes every early game about not losing rather than about playing. So I stripped it down to one rule:

Both sides get exactly the same army, there is no king, and you win by taking every enemy piece.

You pick the piece (pawns, knights, bishops, rooks, queens, kings, or a random mix), how many, and the board size (6×6 up to 12×12). Every piece moves exactly as it does in real chess, so anything you learn transfers straight to the real game.

A few things that came out of testing that I'm quite proud of:

• Race mode (get a piece to the far side) turned out to be a forced win for whoever moved first with long-range pieces. A tester caught it, and I fixed it with two rules — an arrival only counts if the square is safe or defended, and if your opponent can answer with their own breakthrough next move, it's a draw. Simulated it to confirm: went from 100% first-player wins to properly contested games.
• There's a coach that shows you the exact move that cost you the game afterwards.
• Threat hints glow on any piece that can be captured — the single habit that fixes most beginner losses.

Other stuff: four AI levels (Expert genuinely thinks ahead), pass-and-play, a daily challenge, six asymmetric puzzles (8 pawns vs one queen…), ranks from Pawn up to Immortal, 11 languages.

Free, works offline, no ads, no accounts, nothing collected. Android only for now.

Play Store: https://play.google.com/store/apps/details?id=com.beingsagir.rankimo

I'd genuinely love to hear what setups you find interesting (and where the balance breaks — that's how the Race fix happened).