Play a game of chess against Lozza. By default you will be playing with the white pieces. Use the Play menu to change colour and start or restart a new game with with the black or white pieces. You can do this at any time.

You can change how well Lozza plays at any time - including during a game - by using the Strength menu. If you find you are making mistakes, try using a lower strength.

While Lozza is thinking some information is shown above the board and after Lozza has moved the information will look something like this:-

1 s | 948.29 kn | 947.34 kn/s | 0.1%

1 s is the time lozza took to move. 948.29 kn can be thought of as the total number of moves Lozza analysed while making her move. 947.34 kn/s is the number of moves analysed per second. 0.1% is the percentage of her internal memory used so far.

The Analyse button will open a new web page allowing you to analyse the current position. Both web pages will be active. It's easier to bounce between play and analyse pages using a laptop rather than a phone.

Optional URL parameters


You play black. Default is you play white.

l=1 to 10

Sets the initial strength. Default is level 1 (l=1)


Use the specified FEN string to start the game from. The default is the standard start position.


Lozza uses the given UCI go command to make her move rather than that for the selected level. For example to ask Lozza to search to a depth of 2 ply only use:- depth 2

Another example, to ask Lozza to make her move after searching 100000 nodes, use:- nodes 100000

To make Lozza move after a certain time specify the time in milliseconds, e.g. 200ms use:- movetime 200

When the m parameter is present the strength menu has no effect.

Lozza Chess