A game is "Standard" if the expected duration of the game is 15 minutes or more. "Expected duration" is determined by a formula that takes into account both the Start time and the Increment (Inc) value.

Here is the formula: Expected duration = (Start + Inc*2/3)

A game is "Blitz" if the expected duration of the game is between 3 and 15 minutes per player. "Expected duration" is determined by a formula that takes into account both the Start time and the Increment (Inc) value.

Here is the formula: Expected duration = (Start + Inc*2/3)

Thus, a Blitz game is one that is expected to last between 3 and 15 minutes for each player (or from 10 to 30 minutes combined). Lightning games are those with expected durations less than 3 minutes per player, while Standard games are those with expected durations more than 15 minutes per player.

A game is "Lightning" if the expected duration of the game is less than 3 minutes per player. "Expected duration" (etime) determined by a formula that takes into account both the Start time and the Increment (Inc) value assuming 40 moves are played.

Here is the formula: Expected duration = (Start + Inc*2/3)

A game is "Untimed" if the clocks will not be used when playing the game. In this case, both the Start and the Increment are 0. For example, "match friar 0 0" would request an untimed game against Friar. The clocks in an untimed game will not move (though interfaces may handle this in different ways). Also, "flag" will not work since the times will never be below 0 seconds. Lastly, Untimed games are always unrated.

Wild is a little different from the other categories of boards in that the starting positions are non-standard. Because wild games are fundamentally different than regular chess they are rated separately from blitz and standard chess games. The wild ratings, however, do not take into account the time controls; all wild games are rated on the same basis.

Here are the major variations of wild that are rated:

Style 0: White has the typical set-up at the start. Black's pieces are the same, except that the King and Queen are reversed, so they are not on the same files as White's King and Queen.

Style 1: In this variant both sides have the same set of pieces as in normal chess. The white king starts on d1 or e1 and the black king starts on d8 or e8, and the rooks are in their usual positions. Bishops are always on opposite colors. Subject to these constraints the position of the pieces on their first ranks is random. Castling is done similarly to normal chess: o-o-o indicates long castling and o-o short castling.

Style 2: In this variant the usual set of pieces is arranged randomly on the first and eighth ranks, with the constraint that Black's arrangement is always a mirror image of White's. Castling is not allowed.

Style 3: In this variant the set of pieces is randomly chosen (subject to the constraint that there is one king of each color). It is quite possible to get more than the normal number of a given piece, such as three rooks or two queens. The pieces are placed on the first rank behind the pawns, the position of Black's pieces mirrors White's placement, and castling is not allowed.

Style 4: In this variant a random set of pieces is generated. These pieces are placed randomly for White and Black behind the rank of pawns, subject to the constraint that the bishops must be balanced.

Style 5: In this variant, each player has the usual set of pieces. However, they are placed in a very unusal position. Pawns start on their 7th rank rather than their 2nd rank! They are, therefore, one move away from becoming queens. The pieces are placed on their 8th rank rather than the 1st rank. When the game starts, it will look like the board is upside down, with White's pieces starting on Black's side of the board, and vice versa. But don't let this fool you.

Style 8: In this variant, the major pieces are in the normal positions but the pawns are in their fourth rank rather than their second rank.

Bughouse (or siamese chess) is a "wild" variant of chess played between two player teams on two separate boards. The special feature of the game is that pieces you capture are transferred to your partner, who is playing with the opposite color pieces from yourself. He may "drop" such a piece on an empty square as a subsequent move in his game.

STARTING A BUGHOUSE MATCH

First, use the "partner" command to select a partner. Next, find an opponent team. You may use the Team channel for this purpose (channel 25), and the command "who B" lists players who are members of a current bughouse team.
Then, one of your team challenges his desired opponent on the other team to a "wild bughouse" match. (A useful alias for this is "alias bug match @ 2 12 bughouse" where "bug user_name" is all you would need to type in order to match user_name to a bughouse game.)
When the match is accepted and all four players are present, then two games are initiated simultaneously: one between the challenger and the challengee with the desired colors, and one between the other partners, with colors opposite from their partners. The same time control applies to both boards, though "moretime" can be used independently on each board. Each player is notified of the game number of their partner's game, so he may observe it as well as playing in his own game.
To help you form bughouse partnerships and bughouse matches, two channels have been established: channels 24 and 25. Channel 24 is for matches and channel 25 is for partnerships.

PLAYING BUGHOUSE

As you play, you will be periodically notified when your partner passes you captured pieces. You will be told the piece that was passed, and the set of pieces that you are currently holding. You are also notified when your opponent's holdings change. Both player's holdings are displayed whenever your board position is refreshed.
A new move notation is needed to drop one of your held pieces onto the board. The notation for making a drop is "P@fr", where P is a piece you are holding [PNBRQ] and "fr" is the empty destination square.
You may talk to your partner. It is recommended to set up convenient aliases for common messages, such as "I need a knight!!", "Don't give him a bishop!", and "Are you out of your mind?!". The "ptell" command is used for this purpose; only your partner will hear it.
The match is finished when one player is checkmated, resigns, or is flagged. At that point the wild ratings of *all* match players are adjusted, whether or not the team result was because of their game. A draw request should be made and accepted at *both* boards before the match is ended as a draw [a near impossibility].
Note that checkmate is defined differently: there must be no *possibility* of avoiding checkmate by a drop interposition. Even if your opponent is holding no pieces that he can drop, he may later get a piece to interpose from his partner. Thus, only contact and knight checks can give a "decisive" checkmate.

RESTRICTIONS

Pawns cannot be dropped onto your first or eighth rank, although they may be dropped onto the seventh rank and promoted on the next move.
Pieces that had been promoted revert to pawns when captured and passed to your partner.
Your partner variable is not saved between logins. You should set it prior to starting your first bughouse match in a server session and when you want to change partners.
Observers should observe both games to see the full match. Kibitzes and whispers, however, go to observers (and players) of *both* games. Observers will also be notified of pieces transferred to each player's reserves. (Note that kibitz can be used as a shortcut to tell your partner something if you don't mind your opponents hearing it. It also makes the game more exciting for the observers.)
Strength assessment takes held pieces into account.
This mode of play may break client interfaces. Contact the author of your client to determine if you can play bughouse with it. If a client relies on the board position rather than moves, things should work OK. No new styles have been added to support bughouse.

Crazyhouse is a variant of bughouse chess designed for two players. The main feature of this game is that, when you capture an opponents piece, it becomes yours to use as you wish.
A new move notation is needed to drop one of your held pieces onto the board. The notation for making a drop is "P@fr", where P is a piece you are holding [PNBRQ] and "fr" is the empty destination square. For example, if you want to drop a knight on f7, you would type N@f7.
If you are using the chess.net interface, you can also right click on the square you wish to put the piece on, and then click on the piece you wish to 'drop'. The chess.net interface has a 'box' on the side of the board that displays the pieces you hold from capture.