Square Rule (obstacle)
Glossary
How to prevent the king from entering the square of the pawn?
- d5 — Before promoting the "a" pawn to a queen, White builds an obstacle in the path of the Black king.
- a4 — Immediate pawn advance is a mistake.
- exd5 — He is forced to capture; otherwise, White will promote the "d" pawn to a queen. But now the Black pawn on "d5" is an obstacle in the path of the Black king.
- Ke4 — Black king to the square. Draw.
- a4
- Ke4 — The black king is blocked by his own pawn.
- a5 — White wins. Black's own pawn prevents the Black king from entering the square of the White pawn.