77

88

Safe: 3b is in opponent's discard pile(3 of bamboo)

Dangerous: fits opponent's bamboo melds(5 of bamboo)

Unknown: not seen yet, moderate risk(7 of characters, 8 of characters)

Safe: 2d is in opponent's discard pile(2 of dots)

When an opponent is close to winning (few tiles in hand, many melds exposed), you need to play defensively. Safe tiles are ones already in that player's discard pile — they can't win off a tile they already threw away. Dangerous tiles are ones that fit their visible melds or haven't appeared yet.