Variant Sudoku

2-String Kite

When a row and a column each have exactly two spots for a digit, and one end of each sits in the same box, the cell that sees both far ends can’t be that digit.

Practice now
6
1
8
2
9
1
1
1
5
2
1
1
1
2
1
8
7
1
1
2
9
1
8
1
7
6
3
2
6
5
1
9
4
4
1
6
1
7
9
3
7
1
1
1
6
5
1
1
1
2
5
1
6
1
1
1
6
1
7
1
1
1
Clear 1 where the far ends cross.

Why it works

On the board above:

Row 4 has only two spots for 1: r4c5 and r4c3. Column 4 also has only two: r6c4 and r7c4.

r4c5 and r6c4 share box 5, so they can’t both be 1.

If r4c5 isn’t 1, then r4c3 is. If r6c4 isn’t 1, then r7c4 is. So r4c3 or r7c4 is 1.

r7c3 sees both r4c3 and r7c4, so it can’t be 1.

How to spot it

  1. Pick one digit

    Look only at that digit’s spots.

  2. Find a row with two spots

    Then a column with two spots.

  3. Join them in a box

    One spot from the row and one from the column must share a box, in different cells.

  4. Clear the crossing

    Remove the digit from the cell in the far end’s row and the other far end’s column.

Practice

Real boards from the solver, with every pencil mark filled in. Spot it, then use it, then find it cold.

Loading the boards…

Try it in a real puzzle

Each of these needs a 2-String Kite to finish. It opens in the player.

Tips

Only one cell is cleared

The kite nearly always clears a single cell. That makes the answer easy to check.

Think of strings

Each two-spot row or column is a string. The box ties the strings together.

XY-WingThree cells with two candidates each, bent around a middle cell, force a digit into one of two wings.Next: XY-Wing →

In the glossary

2-string kite