Medium sudoku 4

A medium nine by nine, which is the one most people mean by «a sudoku». There is always a next square you can prove, but finding it takes noticing that two cells in a box can only be two numbers between them — the point where scanning stops being enough.

13482678251723743532523615483591
Show the answer key
571394286982165374463782951815976423697423518324851697239618745156247839748539162

What is on this sheet

Given numbers
32
Difficulty
Medium
Hardest step needed
Naked pair
Grid
9 × 9

About this puzzle

Medium means 30 to 35 given numbers, and at least one step that needs a pair or a locked candidate rather than plain scanning. The grid was solved technique by technique to grade it: if it had needed trial and error it would not have been published, and the single answer is printed on the second page.

This particular grid starts with 32 of the 81 numbers already printed, and the hardest technique it asks for is: Naked pair.

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