Chiitoitsu

Chii Toitsu, also known as Chii Toi or Nico Nico, is one of the standard yaku hands. This hand consists of seven pairs, where no two pairs may be identical (i.e. a quad may not be considered two separate pairs). This hand is one of the two exceptions of the "four melds and one pair" rule of forming a hand, where the other exception is the Kokushi musou. This hand is closed only.