The case notes
Let a missing V settle an X chain
Every X and V in this puzzle is shown. That makes an empty edge useful, especially beside a marked pair. Watch a worked example, then try the idea in a puzzle.
Put it into practice
All X and V marks are shown
Every X and V in this puzzle is shown. That makes an empty edge useful, especially beside a marked pair.
X = 10 · bare edge ≠ 5 or 10
The X says these two cells add to ten. The edge down to the given three is bare: it cannot add to five or ten.
Try 8 → X partner 2
Try eight on the right of the X. Its partner must be two, because two plus eight is ten.
2 + 3 = 5 · V missing
But two plus the three below is five. That bare edge would need a V, and there is none. So eight is impossible on the right.
Read the transcript
Every X and V in this puzzle is shown. That makes an empty edge useful, especially beside a marked pair. The X says these two cells add to ten. The edge down to the given three is bare: it cannot add to five or ten. Try eight on the right of the X. Its partner must be two, because two plus eight is ten. But two plus the three below is five. That bare edge would need a V, and there is none. So eight is impossible on the right.
