One point decides everything
In life-and-death and shape, there is usually one vital point (急所) whose occupation decides the outcome: the centre of a 3×3 eye-space, the middle of a straight-three, the key spot that turns a dead shape alive or kills a living one. When defending or attacking a group, your first instinct should be the vital point — the place that, if you don't play, the opponent surely will. The chapters ahead drill exactly these points.