Nullfield

About Nullfield

Nullfield is a logic puzzle by karachr, released free on itch.io for Windows and Linux and also played in the browser on the maker's Daily ROM site. The goal is Minesweeper's: open every safe square and find all the voids without opening one. Revealed squares count the voids among their eight neighbours, and in addition every row and column shows a permanent total of the voids it holds.

Working the edge totals against the counts on the board is the trick the game is built around, and its four-board tutorial teaches it. Every field is checked by a solver before you see it, so you never have to flip a coin. Some squares are safe but hide their number, and those areas have to be worked out from the totals. SCAN charges open a square that is sure to be safe when you are stuck, at the cost of your clean-solve bonus.

There are three sizes, TERMINAL, SUBSTATION and REACTOR, and a DAILY FIELD that changes every day and keeps a streak. On the Daily ROM site, where it sits beside the maker's other daily puzzles, everyone gets the same Nullfield puzzle on the same day, and the difficulty climbs through the week like a newspaper crossword. Scores come from speed, the number of actions and finishing without a scan.

The desktop version works offline with no account, ads or tracking, with mouse, touch and keyboard controls and chiptune sound. It suits Minesweeper players tired of the forced guess at the end of a board.

How to play Nullfield

1. Choose DAILY FIELD from the title screen, or open the day's puzzle on Daily ROM.
2. Read the totals along the top and left edge: each says how many voids are in that column or row.
3. Open a square you can prove is safe; its number counts the voids touching it.
4. Flag squares you can prove are voids.
5. Open a number whose voids are all flagged to clear everything else around it.
6. Clear every safe square without opening a void, using a SCAN only if you are stuck.

Screenshots

Tips

• Start with rows and columns whose total is 0: every square in them is safe.
• A row whose total equals its unopened squares is all voids.
• Do not skip the edge totals; they often crack a corner the board numbers cannot.
• Save your SCAN: finishing without one earns the clean-solve bonus.

Questions