Invent your own chess variant.

That's already been invented. In fact, you could play a game with that criterion right now, on this very website.

Idea for a new chess piece: The die. The die is a piece that can randomly teleport to any square on the board, including one that is already occupied by a friendly piece. If a square is occupied by an enemy piece, then it is captured. However, if it is occupied by one of your pieces, that piece gets captured. If it lands on the enemy king, then you win! However, if it lands on YOUR king, you lose...

then pawns would just take up space in the board. 

idk

I see a problem with that instantly: What if all the pawns advance two squares (i.e. 1. a4 a5 2. b4 b5 3. c4 c5 4. ...)? Then it would be pretty much impossible to mate the other person.

But wouldn't opening theory become completely useless? Natural opening move sequences like 1. e4 e5 would no longer mean anything, because those squares would be off-limits for the remainder of the game.

New variant idea: Multiple Moves Chess. It's essentially just regular chess, except pawns can't move two squares and you get to make as many moves on your turn as you like. However, there are a few terminal moves: If you move a piece to a position where it can be captured, then your turn ends; if you move a piece to a position where it can capture on the next move, then your turn ends; if you capture a piece, then your turn ends; if you give a check, then your turn ends.

Oh yeah, and if you move the same piece three times in a row, you automatically lose.

Bishop bashing chess- anytime you capture your opponents bishop you have to "give him a hand"...... 

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!

Every six moves (six white moves, six black moves) the hour changes. Each hour has its own gimmick. For example: Bishops can't move at 3:00 a.m.

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 like the idea for the cultist (nice Cthulhu reference lol)

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.