Kokushi musou 「国士無双」, also simply known as kokushi or in English as thirteen orphans, is one of the standard yakuman hands. It is one of the three yakuman gosanke 「役満御三家」, or "the three big families of yakuman". This hand is one of the two exceptions of the "four tile groups and one pair" requirement for tenpai hands, where the other exception is chiitoitsu. In fact, hands for this yakuman involve individual tiles while including a pair.