Aspiration search
:
Aspiration search is a small improvement on Alpha-Beta search. Normally the top level call would be AlphaBeta (pos, depth, -INFINITY, +INFINITY). Aspiration search chnages this to AlphaBeta(pos, depth, value-window, value+window), where value is an estimate for the expected result and window is a measure for the deviations we expect from thi s value.
Chess Tree Search
MiniMax and NegaMax
Alpha-Beta search
Aspiration search
Transposition table
Aspiration search will search less positions because it uses alpha/beta limits already at the root of the tree. The Danger is that the search result will fall outside the aspiration window, in which case a re-search has to be done.