The Rule of 45 of Killer Sudoku (innies and outies)

This tip is probably the most important solving technique of Killer Sudoku, one that will save you a lot of time. It does involve some math, but very simple one. Basically, the whole story is that …

In a Killer Sudoku, what's the relationship between these two cells? : r/ sudoku

Ninja Sudoku - Logic hint - Apps on Google Play

Ninja Sudoku - Logic hint – Apps on Google Play

Killer Solving Guide

JSudoku - Innies/Outies Techniques

Sudoku Solver - Killer Sudoku Multiple 45 Rule Solving Technique

JSudoku - Innies/Outies Techniques

Killer sudoku - Wikiwand

Sudoku Mania: Solving Technique for Non-Consecutive Sudoku

Killer Solving Guide

Cage Unit Overlap

Killer Sudoku — Puzzle Page Help Center

How does this work? : r/sudoku

JSudoku - Innies/Outies Techniques

So stuck on this! Not sure where to go next… : r/sudoku