Way back when during the Nice, 1974 Olympiad, the Soviets faced the West German team on June 17th. On the first board, Anatoly Karpov, the then current wunderkind of the Soviet Chess Machine, faced off as White against long time West German Number 1 Wolfgang Unzicker. A typical slow Closed Ruy Lopez followed. Eventually, the following position was reached:
Karpov vs Unzicker
After 23...Qd8
I discovered this position in the 2015/6 issue of New In Chess. Parimarjan Negi wrote about it in his column Parimarjan's Chess Gym. I'll turn it over to him:
A well-known position. Black is ready to exchange rooks along the a-file, after which it will be much harder for White to generate anything on the queenside. Here Karpov played the amazing:
24. Ba7!
This absolutely paralyzes Black's queenside. The rest of the game is elementary technique, as White brought his other rook to the queenside, seemingly with the intention of penetrating via the a-file, but ending up completely suffocating Black, who was keeping himself ready for the bishop retreat that never happened.
An awkward seeming move, but a pretty idea! The rest of the game is a slow, steady squeeze. The whole game is in the viewer below.
