Pens, pencils and a facility with numbers. Also helpful: earplugs, plushies, a water bottle, calming herbal oil and the occasional “wild bifurcation” (a.k.a. a wild guess).

Get started solving the classic number puzzle with tips from some of the best solvers in the world. By Isaac Aronow Everybody can solve a hard Sudoku. Maybe not right now, maybe not without some ...