▲ 3 r/sudoku
Help understanding logic behind why this has to be a 4?
I usually play on sudoku.com and encountered this puzzle. I was able to spot lots of matching pairs (doubles) and a triple, and I also tried searching for XY Wings, but ultimately wasn't able to see any path forward so I used a Hint.
Usually the hint will explain the logic behind the answer however this time it simply filled in the number 4 in the highlighted square (r5c2). No explanation was given.
Can someone explain why that square must be a 4?
Alternatively, if I hadn't used the Hint, what technique/logic should I have applied to figure out the next step on my own?
I love learning and be able to improve my game so any help is greatly appreciated. Thank you in advance!
u/AlannaKitty — 1 day ago