Anti King

Cells a chess king move apart contain different digits.

Parameters

Maths

Class: first-order.

The shared predicates define the notation and every named predicate.

∀a,b ∈ C: king(a,b) → D(a)≠D(b)

For every distinct pair at Chebyshev distance 1: their digits differ.

Example

---
format: open-rules
title: Anti King example
setter: Example
source: ""
case: ""
library: https://rules.sudoku-sleuth.com/
status: read
---

```rules
sudoku 9x9
anti-king
```

Satisfies the rule: r1c1=1, r2c2=5. The cells share a corner and contain different digits.

Breaks the rule: r1c1=1, r2c2=1. A king-related pair repeats a digit.