Invent your own chess variant.

Come up with your own chess variant(s) that could potentially catch on.

I'll start. I don't know what I would call this variant, but it looks really interesting:

I don't understand your variant, that position can occur from a chess960 game.

I've got a funny variant, that wont' catch on. 

I call it 'Imortal Kings' 

The rules go as follows: 

The king can never be captured, the king is allowed to step into check or capture a piece and step into check, but cannot step into checkmate, if you checkmate the opponent's king he can move into check to get out of the checkmate, but if any legal move that side would do, would still be checkmate, then that player wins.

A king can check a other king with his/her king, but cannot capture the other king.

Examples.

when I was a kid we would sometimes let a pawn move one square in any direction.  Still moving 'straight' and capturing diagonally.  It changes the game dramatically 

just a king and a king... and they wander around aimlessly until they find a strip bar...

well, since chess is slowly becoming a solved game, I have my own variant that makes the game fresh(er), requiring more on-spot analysis and less reliance of patterns: the game is set up like chess960. however, a rook and a knight from the opposing side must be flipped to the opponent's side. it takes the best of chess960 and dramatically changes the game structure. I also like the ability to have the pawns move backward and capture diagonally in all four directions. So yeah, Chess960 but much much harder.

The king is like every other piece, so he isn't restricted by checks (neither are other pieces) and there is no notion of a checkmate. But if he is captured, then that player has 8 moves to capture the opponent king to make it a draw. Otherwise he loses.

Bughouse, when 4 players play. If you capture a piece, you give that piece to another person that has the piece color of your opponent. One side wins, the game ends.

I have an idea. I call it Lightning Chess. After every move, a random square is attacked. If there is a piece, then it swaps color. During a person's move,.it will be marked. If the king is on that square, it will be in check.

"Winner has to buy the next round".  Why is this a variant of note you ask?  That's simple.  Because listening to the loser whine "you know I just let you win because I'm cheap, right?" never gets old...

EDIT:Oh and whining when you lose but getting a free beer is fun too. 

Is it the Displacement Chess variant?

"portal chess" with two boards, four players, your teammate plays as one color, you play as the other, and whenever you capture a piece it goes to the same square it was captured on on the OTHER board (even if it lands on an enemy piece.).

Portal chess is a good idea, better than Bughouse. I offer to play it at own topic "Portal chess". By the way two pieces of the same color at complementary squares are untouchable.

How about "booby trap chess"? I've seen "atomic chess", where a piece can explode, but this variant has a secret explosive square. Before the game commences each player secretly writes down the co ordinates of one square on the board. This square can be detonated once per game by a player if an enemy piece lands on it by movement or capture. Any piece on it is removed from play. If an enemy piece lands on the square by capture both color pieces are simultaneously removed. The player must show the written square coordinate to his opponent to show he wasn't cheating. If both players chose the same square then no more squares can be chosen.

Obviously central squares might be the most obvious target but that might allow some bluffing- your opponent may not want to put a piece on a central square in case it's a booby trapped square, meanwhile the square you actually booby trapped might be on the edge of the board.

Let's test em'.

Immortal Kings:

Transposed knights with bishops:

More comin' soon.

KingpinChess created this.

I came up with a simple variant called Elimination Chess. You start off by playing a normal game until checkmate is reached. Then you play a new game, but only using non-captured pieces. This cycle continues until one player has only the king left. It makes you be more careful about sacrifices as they could prove useful in the longrun. If you're not careful, you could be left with seemingly useless pieces. It can create interesting end game out comes such as this

in my game if a piece wants to move somewhere, an enemy piece could capture it before it reaches  the destination. For example,if the bishop wanted to capture the queen, the bishop would be forced to capture it. This also works on knights.

I've seen Accelerated Chess before.

This means you can move either two non-capturing moves, or one capturing move. (Not capturing then capturing isn't allowed)

Example:

However, this time, this is Decelerated Chess. (Or Anti-Accelerated Chess)

Instead, this is two capturing moves or one non-capturing move. (Capturing once is illegal!)

Example: (Try it out!)

I've been fooling around with different chess-like games and chess variants for a while now, And I like the Seirawan / Musketeer Chess idea of having 2 new pieces per game that can be introduced from behind your back row when an appropriate vacancy is created.
I have about 20 pieces I am trying out, but I will only mention 2 original ones here, as their effects are quite interesting:

1. The Juggernaut.  Moves like a rook. Once it starts moving, it CANNOT STOP until it has either captured a piece or reached the edge of the board.  It may capture more than one piece in one move, and amy capture friendly pieces.  (It may be captured the same as any normal piece)


IMPRESSIONS: With the right placement, it can be devastating in the opening & midgame.  It can't be blocked, and can give check though any number of blocking pieces, friendly or enemy.  In the endgame (if it survives that long), it's usually pretty sad, as on an open board, there's little to stop it, so it can't maneuver well enough to be useful - unless you are foolish enough to get in its path!

2. The Dire Nemesis.  Moves like a queen, but always must move towards the enemy king. Cannot be captured, except by the enemy king.  Note that this is a different piece to the Nemesis from Chess 2, which cannot capture, but has free movement.


ANALYSIS:  Being able to capture without being captured makes it seem invincible, but you will soon realise its limitations, and once it get close to the king it is quite vulnerable.  Lack of maneuver options is its downfall.