大毘盧遮那經廣大儀軌 2.31

2.31

次右華臺中，觀訶字放光，
轉成地藏身。地藏同馬頭，
申水風餘拳，是名地藏印。

Next, in the flower pedestal on the right, contemplate the syllable Ha radiating light,
Transforming into the body of Kṣitigarbha. Kṣitigarbha's [mudrā] is the same as Hayagrīva's:
Extend the āp and vāyu [fingers] with the rest in fists; this is called the Kṣitigarbha Mudrā.