---
title: "X-Wing: Sudoku Technique #12 | Sudoku Flow"
description: "X-Wing: When a number is locked to the same two columns in two rows (or to the same two rows in two columns), that candidate is removed everywhere else in…"
url: https://sudokuflow.com/lessons/xWing/
language: en
---

[Sudoku technique lessons](https://sudokuflow.com/lessons/) / X-Wing

Lesson 12

# X-Wing

## The rule

When a number is locked to the same two columns in two rows (or to the same two rows in two columns), that candidate is removed everywhere else in those two crossing lines.

## Step by step

1. In each base row, 4 appears as a candidate in only two cells. These cells line up in the same two column positions, forming an X-Wing!
2. The X-Wing means 4 must occupy one of the two diagonal pairs of these four corners. So in the two columns that hold them, we can remove the candidate 4 from every cell outside the two base rows.

[Read the full lesson, with more examples →](https://sudoku.rubigogames.com/techniques/x-wing.html)

In our app, when this technique is the next step, the hint names it and shows you why, step by step. No ads, free to download.

[App Store iPhone, iPad, Mac](https://apps.apple.com/app/apple-store/id6502922368?pt=125379530&ct=sudokuflow_cta&mt=8) [Google Play Android](https://play.google.com/store/apps/details?id=com.rubigogames.sudoku&referrer=utm_source%3Dsudokuflow%26utm_medium%3Dcta%26utm_campaign%3Dlesson)

## Try it on more boards

Each board is a real puzzle from our app, at a moment where X-Wing applies. Find the step yourself, or tap Hint and the app's own hint walks you through it.

X-Wing practice board:

```text
.  8  .  | 1  4* .  | 2  .  .
4  .  .  | .  7  .  | .  8  5
2* .  6  | 9  5* 8* | .  .  .
---------+----------+---------
8* 5* 2* | 4  1* 9  | 3  6  7*
1  .  .  | .  6* .  | .  5  .
7  6* .  | .  3  .  | .  .  .
---------+----------+---------
.  .  .  | .  2* .  | .  4  1
3  4* .  | 6  9* 1  | 5  .  .
.  2  1* | .  8  4* | .  3  .
```
Digits marked * were filled in by a player; the others were printed with the puzzle.

![Sudoku app icon](https://sudokuflow.com/assets/app-icon.png)

## Want more boards like this?

We also make a Sudoku app for iPhone, iPad, Mac and Android. There are no ads in it at all, it works offline, and when you ask for a hint it shows you the technique instead of just filling in a number.

[App Store iPhone, iPad, Mac](https://apps.apple.com/app/apple-store/id6502922368?pt=125379530&ct=sudokuflow_web&mt=8) [Google Play Android](https://play.google.com/store/apps/details?id=com.rubigogames.sudoku&referrer=utm_source%3Dsudokuflow%26utm_medium%3Dweb%26utm_campaign%3Dsite)

Sudoku Flow is made by Rubigo Games, the developer of the Sudoku app recommended on this site.