AI Can't Tell You Why It Did Something

The problem comes when the database and the engine go from )ach to oracle. It happens quite often that I will ask one of the students about a move from one of their games, and why he made it. If the move comes early on, the answer is almost always, "Because that's the nain line." That is, that's the theoretical move in the database, likely 5layed by many Grandmasters before. Sometimes the move isn't thery, but the student prepared it with the help of an engine, so the anwer is similar: "It's ...

 Tablebases

t. In 1977, Thompson showed up at the World Computer Chess Championship th a new creation, a database that played the king and queen versus king and rook endgame perfectly. (KQKR is the abbreviation.) It wasn'1 an engine; there was no thinking required. Thompson had generated a database that essentially solved chess backwards, what we call retrograde analysis. It started from checkmate and worked its way back until it contained every single possible position with that material balance. Then i...

 Null Move

Called the "null move" technique, it tells the engine to "pass" for one side. That is, to evaluate a position as if one player could make two moves in a row. If the position has not improved even after moving twice, then it can be assumed that the first move is a dud and can be quickly discarded from the search tree, reducing its size and making the search more efficient. Null moves were used in some of the earliest chess programs, including the Soviet Kaissa. It's elegant and a little ironic...