Some endgames can be quite easy to play to mate, but very difficult to play the fastest mating sequence, these problems can be particularly annoying as it can be easy to lose rating points on these type of problem. The "Blitz" button is designed to avoid some of this frustration.

The "Blitz" button allows you to take the option of solving endgame problems under the clock. The "Blitz" button is intended for use on endgames which you feel may be easy to mate , but not easy to play perfectly. After clicking the "Blitz" button, the clock changes to a count down timer and you have until the clock reaches zero to solve the problem. Similar to Practice mode (irrespective of whether you were in Theory or Practice mode to start with), you are able to make any move you like (as long as it is still winning). You will not be punished for moves that take longer than the shortest path to mate. If you solve the problem within the time limit, you will get full points for getting the problem correct. There are no rewards for fast times, you will be marked the same if you have 1 second left on the clock or 50 seconds. If you run out of time, get the problem wrong, or reach a drawn position then you will marked incorrect. You can only choose to blitz a problem before your first move. The number of seconds you have to solve the problem is defined by the function MAXIMUM(60,DTM*3.0+10) where DTM = Depth to mate. The time used before you press the blitz button is also included in the time allowed, so the longer you take to press the blitz button, the less time you will have to solve the problem once the clock starts counting down. When using the blitz button you are required to mate the opponent, currently there is no pruning done when using the blitz option.

To avoid frustration from having to play out endgames against a lone king when blitzing after having already converted from a harder endgame, there are specific conditions under which a blitzed endgame will prune when you reach a position where your opponent has a lone king. If you reach such a position that would normally be pruned in a non-blitzed endgame, and have not used so much time already that you would likely not have time to mate, and have never reached within 2 moves of checkmating up to this point, then the problem will finish without you having to mate the opponent king. Sufficient time to mate is defined by the formula MAXIMUM(10 seconds,DTM*1 seconds). Or in other words if you have at least 10 seconds or 1 second per move to mate left when you reach a lone king position for your opponent, then you will be deemed to have enough time left to mate, and the early pruning check will be made.