Play word 独鈷石 独鈷石 とっこいし ground stone tool from the late Jomon period (named after its similarity to the Buddhist tokko)
Play word 飛行の三鈷 飛行の三鈷 ひぎょうのさんこ three-pronged vajra flung by Kukai on his return from China to determine the Holy Land of Esoteric Buddhism