Rules of Movement

A Bishop 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 that a move is legal only if the absolute difference in file and rank is equal. Let's look at some examples.

Examples

a6 → f1

1. Start Position: a6 = $(1, 6)$
2. Target Position: f1 = $(6, 1)$
3. Calculation:
   • File difference: $|1 - 6| = 5$
   • Rank difference: $|6 - 1| = 5$
   • Result: ✅ Legal Move ( both differences are 5 and equal)

c3 → e5

1. Start Position: c3 = $(3, 3)$
2. Target Position: e5 = $(5, 5)$
3. Calculation:
   • File difference: $|3 - 5| = 2$
   • Rank difference: $|3 - 5| = 2$
   • Result: ✅ Legal Move

b2 → e4 (Invalid)

1. Start Position: b2 = $(2, 2)$
2. Target Position: e4 = $(5, 4)$
3. Calculation:
   • File difference: $|2 - 5| = 3$
   • Rank difference: $|2 - 4| = 2$
   • Result: ❌ Illegal Move

Other Special Notes

• Always stays on squares of the same color.
• Can control up to 13 squares from the center.