Conditional moves allow players to configure specific future moves to be played automatically if the opponent responds with a certain predicted move. They are a bit like "premoves" in Live chess, except that premoves are generally made regardless of what your opponent does next, whereas conditional moves are made only "on condition" of a specific move by your opponent.
For instance, let's say you enjoy playing the King's Gambit (1. e4 e5 2. f4): At the beginning of the game, you could play the move 1.e4. Then, when it is Black's turn, you will see a "Conditional Moves" button to the right of the chess board. (It appears only when it is not your turn).
Clicking the button opens a new screen with a chessboard showing the current position; this board is special because it lets you make moves for both sides. You start by entering Black's move (1. .. e5): This establishes the "condition" on which the next white move will be made (i.e. "IF Black plays e5..."). Now you enter White's response: your conditional move (2. f4).
That's all there is to it! The sequence of moves is saved automatically as you go. You can keep going if you wish, entering subsequent moves for black and programmed responses for your own pieces. (You can add as many as five moves for each side.) If you change your mind, you can jump back and correct a given move - or delete the whole line and start over.
If you are a premium member, you also have the ability to set up multiple lines of conditional moves. That means that you can have more than one branch of possibilities: for instance, you could save one line (IF Black plays 1. ..e5 THEN I play 2. f4), and then start a new line at the beginning, in case Black does not play e5 but something else, e.g. IF (instead) Black plays 1. ..e6 THEN I play 2. d4. And so on!
Conditional moves are a great way to save time in positions where the next few moves are predictable - especially during exchanges or combinations where one player's moves are forced, without much (or any) choice.
keywords: conditional programmed trigger triggered moves move