大毘盧遮那成佛經疏 13.53

13.53

Next is the Tathāgata's Hook (Aṅkuśa) Seal. First, with the space finger of the left hand, press the tips of the remaining four fingers to form a ring shape; next, insert the three fingers of the right hand into the ring; place the right thumb over the outside of the left thumb, bending it into the palm to press the three fingers of the right hand, also making them like a ring shape; extend the right wind finger and slightly bend the third joint into the shape of a hook; that is it. Making this hook seal can summon all buddhas and bodhisattvas of the ten directions, causing them all to assemble at the bodhimaṇḍa, and can also fulfill the stations of the ten bhūmis; how much more so for the classes of the remaining eight kinds of beings who have not yet generated a wholesome mind—how could they not arrive?