Houdini Aquarium 2019 & ChessOK Aquarium 2023
ChessOK Aquarium 2023 is a new powerful analysis, database and chess publishing tool, powered by the world's strongest chess engines.

ChessOK Aquarium 2023 €39.96
Houdini 6 Aquarium 2019 €53.95

ChessOK.com » Opening Tree Mode

The Opening Tree mode from our chess bestseller – Chess assistant - is now available online! You can now receive detailed statistics on all opening moves carefully classified and stored in our opening database. From the very first move of a chess game we supply you with as much info as possible:

Games The number of games where this move has been played.

If it is only one game – you can click on it and see who played it, when and where it happened and the game result

White Won The percentage of games won by White when playing this move.

Black Won The percentage of games won by Black when playing this move

Draws The percentage of games ended in a draw when playing this move

White Elo The highest ELO rating of the players who played this move for White.

Black Elo The highest ELO rating of the players who played this move for Black.

Year The most recent year in which this move has been played.

You can move a piece by clicking and dragging it to another square or by selecting the correspondent move from our openings table. The game can be re-started from the initial position at any time by clicking "Clear"

You can switch to any set position using the commands "Load PGN" or "Load FEN".

Load PGN Using the Clipboard you can enter a notation in PGN format from any game and click Load PGN. The chess board will load the position from the inserted PGN line.

Load FEN To insert a position from a program supporting FEN standard (e.g., Chess Assistant) you can copy the current position from this program to the Clipboard (for Chess Assistant – clicking “CTRL” and “\” at the same time) and insert it to Load FEN. After that click Load FEN and the inserted position will upload.

You can copy the moves in the PGN line above the statistics table and it’ll be a full PGN file that can be inserted into any chess program. You can also change the appearance of your chess pieces or flip the chess board. A Takeback function allowing you to go one move back is also available.