Hitori (BrainBashers)

About Hitori (BrainBashers)

Hitori is a shading puzzle: rather than writing numbers in, you take them out. The grid begins full, with many numbers repeated along rows and columns. You mark squares black to eliminate duplicates until every row and column shows each number at most once. Two rules keep it honest: black squares may not touch each other horizontally or vertically (diagonal contact is fine), and the remaining white squares must all connect into one area.

BrainBashers, run by Kevin Stone, posts Hitori grids at 5x5, 6x6, 7x7, 8x8 and 9x9 every day, each at Easy and Medium, plus a 12x12 weekly special. Each puzzle sits on its own dated page with check, answer, print and restart buttons, an option to show mistakes when checking and an optional clock, and the help page has a walkthrough of a full solve.

The set changes at midnight GMT or at the time zone you choose, and the date list keeps the last few weeks. The site has no adverts and no account.

It suits players who like logic with no arithmetic at all, and the connectivity rule gives the larger grids a satisfying endgame.

How to play Hitori (BrainBashers)

1. Open the Daily Hitori page and pick a size and level from today's grids.
2. Click a square to shade it black and remove that number; click again to mark it as white if you are sure it stays.
3. Keep going until no number appears twice in any row or column.
4. Never let two black squares touch side by side, and keep all white squares connected.
5. Press check, or reveal the answer; new grids arrive after midnight GMT.

Tips

• In a pattern like 3 x 3 along a row, the middle square must stay white, since one of the outer threes has to go.
• Every neighbour of a black square is white, so mark them straight away.
• Watch for black squares that would wall off a corner; that square must be white instead.
• A number that appears only once in both its row and column can usually stay white.

Questions