Two connected pawns with same-coloured bishops win as a rule, but the attacker must keep the pawns protected and advance them side by side while the king leads. Careless pushes let the defender attack a pawn from behind.
With bishops of the same colour, two connected central pawns are enough to win, but the technique is slower than most players expect. Every pawn advance creates a square the enemy bishop may attack, so the pawns must be shepherded by the king.