Terra X by Sam Cappleman-Lynes
or solve online (using our beta test of Penpa-Edit tools; use tab to shift between number entry and shading modes.)
Theme: Mystery Box
Author/Opus: This is the 12th puzzle from guest contributor Sam Cappleman-Lynes.
Rules: Place a number from 0 to 9 into each area so that no two areas that touch orthogonally share the same number. Wherever four areas meet at a point (marked with dots as a visual aid), the numbers in those areas must add up to 10.
Also, see this example:
Difficulty: 4.5 stars
Time Standards (highlight to view): Grandmaster = 14:45, Master = 21:00, Expert = 42:00
Solution: PDF and solving video.
Note: Follow this link for other less common Number Placement puzzles.