Lesson
Black to move. Main line: 1... Rd6 2. h3 Rd3 3. Ra4 Rxh3 4. Ra1 Rh2 5. Rb1
1...Rd6! places the rook on the sixth rank, ready to check from the side and attack the pawn. Passive defense behind the pawn would let White coordinate king, rook and pawn without harassment.
After 2.h3 Rd3 3.Ra4, Black takes the pawn with 3...Rxh3. The white rook cannot protect h3 and shelter the king from lateral checks at the same time; once the pawn disappears, rook against rook is an elementary draw.
The Vančura position is one of the essential rook-ending defenses alongside Philidor. Its conditions matter: the defending rook needs checking distance, the attacking king must be cut off from shelter, and the defender must act before the pawn reaches the seventh rank safely.