Invent your own chess variant.

Warzone:

New Pieces/Gameplay Additions : Bomb Spears, Soldiers and artillery

Spears: atomic spears fall from the sky every five turns and decimate every piece in a 3x3 radius

Soldiers: they come out at random and you can control them using a joystick that will appear on screen, middle is a bullet button which when pressed kills the closest piece in that vertical row

Artillery: Same moving mechanic as soldiers, fires shells which explode every enemy piece in a 4x3/3x4 range, can only be fired 3 times, you can convert your queen into artillery or take the enemy's queen/any queen they may produce with pawn promotion and vice versa

i call mine, Zombie Chess. a single player practice board.

there are infinite rounds untill white gets checkmated

Player 1 would always be white. white sets up their pieces normal while blacks pieces arent visible untill the first wave starts. sometimes the wave doesnt have a king. if so you would have to capture every piece to move on to the next. if there is a king you can capture the king and all black pieces will automatically captured. if there are no legal moves for black white loses. if whites king gets captured (no check or checkmate) they lose. one last rule is that if white loses enough pieces they could choose 1 pieces to be back. when a wave is complete all whites pieces still remain at the same places and white goes again when the black pieces reapear. also the waves get harder and harder with more black pieces, only a true GM would make it past i guess. black could still be a human, or ai. ai's difficulty would be simple. how often will the king move its in check? or how offensive it will play? who knows. heres some example. 

its really simple. just a little practice and someone could master this master piece!

Alright, here's a try.

The board is 11x11.

Both sides start with a king and queen, which are quite different from the king and queen in chess. Both pieces are royal. If either is checkmated the game is lost. They can still check another royal piece even if capturing it would put them in check.

Royal pieces can also castle. Castling works differently than in chess. When castling, the castling (royal) piece must not move from check, through check, or into check. The other piece, any piece, must simply be able to move immediately to the square the castling piece has just crossed. Both moves are considered to happen simultaneously. Royalty may castle with any friendly piece. There is no way to lose castling rights. Either player may castle as often as they wish.

There is a special type of castling. The royal castle. Royal pieces may move normally when castling, and this isn't considered a royal castle.

Royal castling is when royal pieces use their castling move in order to be castled with by the other royal piece. If they do, then both the castling piece and the piece being castled with must not move through or into or out of check.

The king moves peacefully as a Wazir., 1 square orthogonally. He can capture as a bishop. The king castles by moving at least two squares peacefully as a rook.

The queen moves exactly opposite the king. She can move peacefully as a Ferz, 1 square diagonally. She can capture as a rook. The queen castles by moving at least two squares peacefully as a bishop.

Guarding the king and queen are some powerful pieces.

First, we have the fortress. The fortress moves and captures as a wazir, but twice in one turn. It can capture on both moves, giving it the ability to take defended pieces. However, because it moves twice, it is colorbound. It can return to its original square.

Next we have the palisade. It moves and captures l as a wazir, but can only be captured by taking it on the square it occupied after it moves, via en passant (with any piece). It is invulnerable if it doesn't do anything, but it's also possible to trap it by pinning it to itself.

Next, we have the cultist. This piece moves first as a bishop, then as a Ferz, 1 step diagonally in any direction. Meaning it cannot take a piece adjacent to itself or move one step toward a piece two squares away. But it can threaten an enormous number of squares.

Next we have some minor pieces. The javelin moves peacefully as a ferz and attacks forward, able to bypass squares that are more than one step from its starting position or its target, making it not a strict subset of the queen's mobility, as it is able to jump to an extent.

There are two compound leapers, the Cobra and Beast. The Cobra moves as an Alfil or Threeleaper and the Beast as a Zebra or Fourleaper. The Cobra is worth about the same as a knight on this board. The Beast is worth substantially more than a knight but probably somewhat less than a rook. Though its long unblockable move threatens to fork pieces.

Next, we have the peasant. This piece moves as a Wazir. However, it can make up to two Ferz moves through friendly pieces first, allowing it to theoretically attack up to 24 squares and making it a potent defensive piece. It can however have difficulty retreating, and if caught in the open it's very vulnerable.

Next we have the wasp. This piece moves similarly to the Rose from Ralph Betza's chess on a really big board. However, it moves horizonally as a knight and vertically as a Dababba. is much weaker than the rose, being constrained to a quarter of the board and having less and shorter range mobility overall. It can only reach half the columns on the board. All four parities of wasp can be created through pawn promotion.

The bee is just like the wasp but rotated 90 degrees. Its vertical moves are as a Knight and its horizonal moves are as a Dabbaba, and it also rides in a circle like a rose. It is equally constrained to a quarter of the board, but it's a different, but possibly overlapping quarter than the wasp. Only three parities of bee can naturally occur, two by promotion and a different one at the start of the game. The one shown here, which can reach the exact center of the board, will never occur naturally. The 27 squares this bee could reach are permanently bee-immune.

Finally, we have two variants of the pawn. One called the guardian pawn captures and moves forward and sideways as a Wazir, and another called the berserk pawn, which does so forward as a Ferz. Both can two square advance aggressively or passively from their 3rd row. The guardian pawn may two square move or attack sideways on the third row multiple times, though is vulnerable to en passant by other pawns when doing so. Both can promote to any piece on the board on their 9th row (the opponent's third row).

There are also traditional FIDE pawns, rooks, and knights in play, and they behave as normal.

The overall board layout looks like this. Note that white's queenside is black's kingside. I have found this often reduces white's advantage by discouraging symmetrical variations.

This means that there are 6 guardian pawn opening moves, 16 berserker pawn opening moves, 8 FIDE pawn opening moves, 4 knight opening moves. 6 Cobra opening moves. 6 beast opening moves, 8 peasant opening moves, 3 bee and 3 wasp opening moves. For a total of 30 ways to open with a pawn and 30 ways to open with a non-pawn piece. Note that javelins, rooks, fortresses, palisades, kings, queens, and cultists do not get to move first. Cultists in particular are very slow to get out.

Revision 1: made javelins are a bit stronger and more unique because they can jump at long range. Made cultists a bit less lethal since they start in the back row behind a particularly slow piece, forcing them to wait until move four to get out of the back two ranks. Also they can no longer checkmate a queen that has never captured, and can't dominate a fortress because they are on different colored squares. Though promoted pawns can become cultists and do those things.

Revision 2: drawing rules are as follows:

1. stalemate is considered a draw. A stalemate occurs any time there is no legal move, including a passing move, for the player who is supposed to move, but they are not in check. This should be relatively rare, though it certainly isn't impossible.

2. repetition: if a position is encountered three times with the same player to move, the game ends in a draw. Emphasis on "same player to move." Passing moves do not immediately increase the repetition counter.

4. 40 move rule. If 80 half moves have taken place and without forward pawn moves (sideways ones don't count) or captures, either player can offer an ultimatum. Either accept a draw now, or the move counter is reset but the next time it reaches 80 half moves without captures or forward pawn moves, the player who refused the draw loses the game immediately.

5. Strictly speaking there is no such thing as a draw by insufficient material. As both of the royal pieces are capable checkmate by royal pin, however, if a moderator is present, positions where it is clear that neither player can force mate or is likely to blunder it, a book draw may be declared.

Revision 3: the peasants are meant to be good at defending, but the fact that the front two end up defending 12 pieces each in densely packed formation while still having 3 extra capture mobility is a bit much and makes it too easy to play solidly. As such, I am changing their move pattern so that they move diagonally twice through a piece and then move orthogonally once. This makes them an alternating color piece and also means they no longer can pass their move. It also means they can't usually retreat after a move. There are still 8 peasant openings but they are now on different squares. And they still manage to defend 30 pieces between 4 of them.

Here is the first ever (read: very bad) game of me playing my variant against myself. Obviously castling forward so early was a big mistake.

Hmm. I think for revision 4, gameplay would improve if there were 4 javelins instead of 4 peasants. The peasants are just too good at locking everything down.

However, this weakens the light squares substantially. So maybe we need to replace the FIDE pawns with guardian pawns?

I feel like being able to attack on two square advances is a little strong. I might playtest a version where pawns can only move peacefully on double advances.

Interesting but way too drawish. A bare queen can probably prevent forced checkmate against almost any army.

Like, here's a position that should definitely never happen. White is up an absolutely ridiculous amount of material (29 points) in a pretty advantageous position against a bare royal queen. Black to move. Can white checkmate here? In how many moves?

In fact, I'll go one step further, is there even a clear way black can blunder mate in this position? Are any of the green moves clearly losing?

I would say at high levels of play chess is a rather drawish game on its own. Which is one reason why I try to make checkmate easier to achieve by having multiple royals, powerful pieces available by promotion or other means, or weaker royals, and compensate the risk of early game mates by giving the player better starting defenses. Making the objective way harder AND essentially robbing the player of any piece that can actually achieve that objective would probably need to come with a total overhaul variant where checkmating a queen is completely reasonable because you can do something like spawn in pieces or start with / promote to incredibly strong pieces actually to the task of checkmating a queen.

How about this: that the pawns don't promote but rather the chess board's edges are wrapped around infinitely, so going off the edge would bring you back to the opposite edge?

I have a similar idea to introduce an unpredictability factor into chess. Have had the idea for a while now, I think it would still work.

It's called 'Carousel Chess' - after every move, the center (the square composed of the four squares d4, d5, e4, and e5) rotates 90 degrees clockwise. So a pawn on e4 moves to d4, then d5, then e5, etc.

This is to train focus on the center and getting used to the idea of tempo - to time maneuvers according to how pieces will likely stand in the future instead of on how they stand now.

This can get complicated quickly and would be a bit difficult in OTB, but it can work.

@Chess.com I have fabricated some other ideas, too.

Hi,

I think that can work with one simple addition! Adding a tempo to the die. So it introduces a new attack on a piece, and then the player has the next move to bring that piece to safety - if he wants to. This way you can get your king or queen out of danger so the game stays playable and doesn't just terminate. It would make play more dynamic and attacking.

That said, i do believe that an element of true randomization does away with some of the logical essence of chess - random moves should still be dictated by an inner logic, i.e. calculable - they should only add unpredictability, not total randomness.

Stalemate chess that works!!!! Objective: place YOUR king in an unmovable position to win. Players  start with zero pieces on the board. On your turn you can choose to place a piece anywhere  on the  board or move a piece you already placed. Pieces cannot be captured unless your opponent places there king in an unmovable position or when all your pieces are placed on the board.Pieces that are captured simply return to you to be used again on another turn rather then being gone or taken by your opponent.I Your king can be placed on the board and removed at anytime at the cost of a turn.If you put your king in an unmovable position and your opponent cannot allow it to move your opponent can  put his king in an unmovable position. If you allow their  king not to move while they can’t move yours then it’s a draw.What makes this idea more interesting is that you start with the opposite colored king and that is your king you are trying to stalemate.

You need more powerful pieces and the ability to checkmate without being up like 16 points of material.

Piecemate chess.

Players may on their turn move a piece or place one onto the board. The game begins with white placing a king and black following suit. These are the only kings that can be placed. Losing one of them ends the game.

Pieces may not be placed in such a way that any piece is attacked.

Pieces can attack squares but directly capturing is not actually allowed. Instead, if one of your pieces is in such a position that it is no legal move could take it out of danger, it is removed.

All Pieces are cowards who move to squares which are attacked by the enemy. But they can move into a position to attack an enemy piece, and they may end their turn under attack if they could escape.

Piece ordering rule:

You must have 2 more of the next lowest tier of piece to play a higher tier.

tier 1. elementary pieces: Wazir, Ferz, Alfil, and Dababba.

tier 2. Minor pieces: knight, camel, cobra (Alfil-Threeleaper hybrid), bishop.

tier 3. Major pieces: rook, Gnu (camel-Zebra hybrid), Knightrider, Missionary (Camel-Bishop hybrid)

tier 4. Queen strength pieces: Queen, Empress (rook-knight hybrid), Princess (bishop-knight hybrid), Bactrian centaur (King knight camel hybrid).

tier 5. Amazon strength pieces: Amazon (Queen-knight hybrid), Lion (double-moving king), ICBM (leaping queen).

So in other words, the fastest order you can play if nothing gets taken, is k,1,1,2,1,2,3,1,2,3,4,1,2,3,4,5. There definitely won't be Amazons and whatnot on the board by move 16 though because in practice most people will move and checkmate some pieces by then. Also it's not always advantageous to play better pieces because remember, you cannot play then in places where they attack the opponent. A Ferz is in some ways better than a Lion because the Ferz can be placed literally in front of the enemy king. However, it is also the case that powerful leapers are very difficult to remove from the board.

It's also worth mentioning that moving effectively costs you a piece. However, at a certain point, it becomes more advantageous to move than squeeze whatever piece in without attacking or being attacked.

I've got a variant idea:

I don't really have a name for it yet, but the rules are as follows:

When a piece/pawn gets captured(NOT by a knight), a new "dead" version of that piece moves one square in the direction the piece/pawn moved to capture it. The new "dead" version can be captured again to remove it from the board. If the "dead" piece/pawn "moves" outside of the board, or on another piece/pawn, it is automatically gone from the board. If a piece/pawn gets captured BY A KNIGHT, the "dead" piece/pawn now "moves" just like the capturing knight did.