Omission Practice Puzzles

Every puzzle below is verified to feature the Omission as its hardest required technique — of the 65,284 puzzles in our library, 41,758 require it and 3,857 need nothing harder. New to the pattern? Learn the Omission or see a worked example first.

How to drill the Omission

Omission — also called pointing and claiming, or box-line reduction — is the most undervalued technique in Sudoku, and these puzzles exist to force it into your regular scan. It works on the intersection between a box and a line: if every remaining home for a digit inside a box falls on one row, that digit is somewhere on that row segment, so it can be struck from the rest of the row outside the box. The same argument runs in reverse, from line to box.

It is worth drilling separately because it is cheap. It needs no pencil marks beyond knowing where a digit can go, it fires constantly in medium puzzles, and solvers who skip it end up reaching for pairs and triples to do work that a two-second box-line check would have done.

When practising, get in the habit of checking both directions every time you look at a box. Most missed omissions are the line-to-box direction, which is less visually obvious than the pointing case.

Curated Omission puzzles

  1. Practice puzzle #1 — 24 givens · needs Naked Single, Omission
  2. Practice puzzle #2 — 23 givens · needs Naked Single, Omission
  3. Practice puzzle #3 — 24 givens · needs Naked Single, Omission
  4. Practice puzzle #4 — 25 givens · needs Naked Single, Omission
  5. Practice puzzle #5 — 25 givens · needs Naked Single, Omission
  6. Practice puzzle #6 — 24 givens · needs Naked Single, Omission
  7. Practice puzzle #7 — 23 givens · needs Naked Single, Omission
  8. Practice puzzle #8 — 24 givens · needs Naked Single, Omission
  9. Practice puzzle #9 — 25 givens · needs Naked Single, Omission
  10. Practice puzzle #10 — 25 givens · needs Naked Single, Omission
  11. Practice puzzle #11 — 26 givens · needs Naked Single, Omission
  12. Practice puzzle #12 — 24 givens · needs Naked Single, Omission
Get a fresh Omission puzzle →

Omission practice FAQ

How many Sudoku puzzles require the Omission technique?
Of the 65,284 puzzles in the Precision Sudoku library, 41,758 require the Omission to solve, and 3,857 can be completed with nothing harder than the Omission. Every puzzle is verified by a solver that records the exact techniques needed.
What is the difference between pointing and claiming?
They are the two directions of the same argument. Pointing runs box to line: if a digit's only homes in a box lie on one line, remove it from that line outside the box. Claiming runs line to box: if a digit's only homes in a line lie inside one box, remove it from the rest of that box.
Why practise Omission separately when subsets seem more powerful?
Because it is far cheaper to spot and it fires more often. Reaching for a Naked Triplet to make an elimination that a box-line check would have produced immediately is the single most common source of avoidable time loss in the middle of a puzzle.