Suited tile
Suited tile
In a real game, you cannot see an opponent’s hand.
But you can see the tiles they discard.
You do not deal into a riichi player with a tile they discarded, because they are in furiten on that tile and cannot ron on it.
A tile the riichi player has already discarded is called genbutsu. It is the safest tile.
Discard one of toimen’s genbutsu.
You picked . Toimen has not discarded it.
Toimen has already discarded this tile.
Toimen is in furiten and cannot ron on 4-sou, but it is not a genbutsu toimen discarded.