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Frequently Asked Questions

Table of contents


What is bughouse (doubles)?

Bughouse is a chess variant played in team of 2 people on 2 boards: when a piece is captured by a player, it is given to his partner who can add the piece on his own board.

What does it mean to drop a piece?

In bughouse, you can decide to add (drop) a piece to your own board instead of playing a move.

What is a player's hand?

In bughouse, you can drop the pieces given by your partner on your board. Before you do so, you keep those pieces in your hand.


What are the different types of puzzles?

Currently, the website only supports puzzles where the solution is a checkmate. There are still different ways to checkmate:

We plan to add different types of puzzles in the future.

I played the correct move according to the website, but it says I failed the puzzle. Why?

If you need a piece from your partner, make sure you asked the piece from your partner before you play the first move on your board, even if you don't need it right away. We chose this ordering because we felt it is important in real games to know which pieces you would need in the future.

I played a move I am sure leads to a checkmate, but was marked wrong. Why?

Only the shortest checkmates are accepted as the solution to the puzzles. We chose to only accept the shortest checkmates because time is very important in bughouse.

A possibility is that you found a checkmate that requires asking a piece from your partner, but there's a solution, possibly requiring more moves, that don't require asking a piece. In this case, only the latter will be accepted, as we consider it faster than asking a piece to your partner.

Another possibility is that you might have found a checkmate on your partner's board, but it isn't the turn of your partner to play. You cannot ask/give a piece to your partner if it isn't your partner's turn.

Yet another possibility is that you asked a piece to your partner, but if your partner captured the piece, he would get checkmated. Thus, this is not an accepted solution, because you would lose the game.

I've just solved a puzzle, but I didn't gain any ELO points. Why?

You only gain points when the website chose the puzzle. This means if you entered the URL of a puzzle, you won't gain any points.

How can I know whose turn it is to move?

There is a small colored circle at the left side of the board, either at the bottom or at the top, right next to the player's hands. You can look at the second tutorial to have a better indication of where it is.

Where can I learn how to use this website?

Look at the tutorial.

Can puzzles have multiple solutions?

Yes. If there are multiple checkmates in the same amount of moves, all of them will be accepted. However, if there's a checkmate that requires asking a piece to your partner and a possibly longer checkmate without needing a piece from your partner, the one requiring another piece will not be accepted as it is considered longer to ask a piece since it requires players' interaction in a real game.

What are the arrows with a number that I can see next to 'Replay solution' after a puzzle is solved?

Those arrows allow you to vote your appreciation of a puzzle. The up-arrow is to indicate that you liked the puzzle, while the down-arrow means you didn't like it.

Please use the down-arrow to indicate any issue in the puzzle, like a missing variation, or if there is a shorter checkmate or some confusion about the correct solution.

I don't know the solution to a puzzle; how can I can a hint?

You can click on 'See next move' at the bottom right (desktop version) or bottom(-left) (mobile version) of the screen to see the next move and continue solving the puzzle.

I see a small pawn in the bottom right corner of a piece. What does it mean?

It means this piece was promoted from a pawn. It is important to know because this piece will be transferred as a pawn to your partner if it is captured. See the tutorial 5 for more explanation.

How to navigate in the move history?

You can either click on the arrows below the move history, use the arrow keys on your keyboard, or click on the move. Look at tutorial 5 for more explanation.

The solution requires asking for a piece, but the piece was not required to checkmate. Why?

The piece was required to checkmate, but the computer chose a variation, possibly longer, that doesn't require the piece to be used. It would have been used if the computer chose a different move, but it tries to play the best move, e.g. the move that allows it to stay alive the longest.


How can I add a puzzle to favorites?

Simply bookmark the URL in your web browser.

How can I view my statistics and recent problems?

Go in your user profile by clicking on the top-right menu and then Profile.

Where can I see a ranked list of all users?

Click on Ranking in the top bar.

Will other types of puzzles be provided in the future?

Yes. Puzzles where the goal is to win material and other types of puzzles will be added in the future. We also plan to add features other than puzzles to help you improve your bughouse play even further.

Playing on mobile devices? has been developped to work on both computers and mobile devices. If you want to enjoy the best experience on smaller screens, we recommend to play in horizontal mode.

Account settings

How can I change my password?

Go in your settings by clicking on the top-right menu and then Settings.

How can I change my email address?

Go in your settings by clicking on the top-right menu and then Settings. Then, click on 'Change email'.


Where can I buy a membership?

Go in your membership page by clicking on the top-right menu and then Membership. Then, click on 'Subscribe'.

How can I cancel my membership?

Go in the membership page and click 'Cancel subscription'. You can also click on 'Customer Portal' in the same page and cancel your membership from the Stripe payment provider website. After cancelling your subscription, you will still be able to use your membership until its expiration date.

How do I change my credit card info?

Go in your membership page and click on 'Customer Portal'. You will be redirected to the Stripe payment provider website where you'll be able to click on 'Add payment method' and follow the instruction. You can also remove your expired card by clicking on the '...' button next to it and then 'Delete'.


My question was not answered here. How can I contact you?

Go in the contact page by clicking on 'Contact form' in the home page.