Chess End-Game: King+Rook versus King+Pawn on a7 (usually abbreviated KRKPA7). The pawn on a7 means it is one square away from queening. It is the King+Rook's side (white) to move.

Sources:

- Database originally generated and described by Alen Shapiro.

Donor/Coder: Rob Holte. The database was supplied to Holte by Peter Clark of the Turing Institute in Glasgow.

Taken from: http://archive.ics.uci.edu/ml/machine-learning-databases/chess/king-rook-vs-king-pawn