Rules of Movement

The Rook is a piece that can move only in straight lines.

A Rook can move from a square $(file_1, rank_1)$ to another square $(file_2, rank_2)$ only if the following condition is met:

This means it can move either vertically (up or down) on the same file, or horizontally (left or right) on the same rank.

Examples

a1 → a8 (Vertical - Valid)

1. Start Position: a1 = $(1, 1)$
2. Target Position: a8 = $(1, 8)$
3. Calculation:
   • File difference: $|1 - 1| = 0$ (same file)
   • Rank difference: $|1 - 8| = 7$ (different rank)
   • Result: ✅ Legal Move

d4 → h4 (Horizontal - Valid)

1. Start Position: d4 = $(4, 4)$
2. Target Position: h4 = $(8, 4)$
3. Calculation:
   • File difference: $|4 - 8| = 4$ (different file)
   • Rank difference: $|4 - 4| = 0$ (same rank)
   • Result: ✅ Legal Move

c3 → f6 (Invalid)

1. Start Position: c3 = $(3, 3)$
2. Target Position: f6 = $(6, 6)$
3. Calculation:
   • File difference: $|3 - 6| = 3$ (different file)
   • Rank difference: $|3 - 6| = 3$ (different rank)
   • Result: ❌ Illegal Move