Anti Knight

Cells a chess knight move apart contain different digits.

Parameters

Maths

Class: first-order.

The shared predicates define the notation and every named predicate.

∀a,b ∈ C: knight(a,b) → D(a)≠D(b)

For every in-board pair separated by (±1,±2) or (±2,±1): their digits differ.

Example

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

```rules
sudoku 9x9
anti-knight
```

Satisfies the rule: r1c1=1, r2c3=6. The cells are a knight move apart and contain different digits.

Breaks the rule: r1c1=1, r2c3=1. A knight-related pair repeats a digit.