Sakazuki (盃, Sakazuki) is a ritual of exchanging sake cups as a means of pledging loyalty. The word itself refers to ceremonial cups used on special occasions like weddings, tea ceremonies, etc.
There are currently two known versions of the sakazuki ritual: the 5:5 pledge and the 7:3 pledge. The former denotes equality between those drinking the pledge, tying them together like siblings. The latter is a pledge between master and servant. This is also done in the Japanese yakuza.