Umbra

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Split the grid into fields of light and shadow, each as big as its number.

Play Umbra

on greatest.games

Umbra is a daily light-and-shadow logic puzzle. Some cells come coloured with a number; you colour every other cell light or shadow so that each field, a run of touching cells of one colour, holds exactly one given and covers as many cells as its number. Two fields of the same shade may never share an edge, and question-mark givens appear later in the week.

About Umbra

Umbra divides a grid into fields of light and shadow. A field is a group of touching cells of one colour, and touching means sharing an edge; meeting at a corner does not count. Some cells arrive already coloured and numbered. These givens cannot be changed, each field must contain exactly one, and the number says how many cells the field covers.

Because two same-coloured fields that touched would merge into one, no two fields of the same shade may share an edge. A given marked with a question mark works the same way, but its size is hidden and must be worked out from the fields around it; no field is ever larger than six cells. Question marks appear from midweek and become more common toward Sunday, while Monday and Tuesday have none. You tap a cell to cycle light, shadow and empty, or drag to paint a run, and a number fades once its field is the right size.

Umbra is one of the daily games on Greatest Games, a site of word and logic puzzles. A new puzzle goes up every day at midnight US Eastern, the same for everyone, and it plays free in the browser with no account or download. A free account opens the Umbra archive of every past puzzle by date.

How to play Umbra

Open Umbra on greatest.games and look at the coloured, numbered givens.
Tap an empty cell to make it light, then shadow, then empty again, or drag to paint.
Grow each given's field to exactly its number of cells.
Keep fields of the same colour from sharing an edge.
Fill every cell to finish.

Tips

Start with 1s: they are complete already, so their neighbours must be the other colour.
A cell between two same-coloured givens of different fields must take the other colour.
Remember no field exceeds six cells, which limits question-mark givens.
Corners do not count as touching; use that to separate fields.

Questions

What counts as a solve?

Every cell coloured light or shadow, each field holding exactly one given and covering that many cells, with no two same-coloured fields sharing an edge.

What does a question mark mean?

A given whose size is hidden. Work it out from the fields around it; no field is larger than six cells.

When does Umbra reset?

Every day at midnight US Eastern Time, with the same puzzle for everyone.

Is Umbra free?

Yes. It plays free in the browser with no account. A free account unlocks the archive of past puzzles.