Sentinels #157

• Last cell in a region. Every coloured region holds exactly one sentinel. A region down to a single open cell is solved.
• Region locked to a line. If every open cell of a region sits in one row, that region’s sentinel is somewhere in that row - so no other cell in the row can hold one. Cross the rest of the row out.
• Last cell in a row. Every row holds exactly one sentinel. When a row has only one cell left that is not crossed out, that cell must be the sentinel.

Every one of these is explained properly in the Star Battle technique guide. New to the genre? Start with Star Battle Puzzles.