sentence1: In the dohyo, a raised mound of hard clay some 4.6 m (15 ft) in diameter under a large suspended Shinto-roof-style canopy,toss salt across the dohyo to purify it of evil spirits, swagger around, and commence the all-important  psyching-out  of the opponent.
sentence2: Salt is tossed in order to purify dohyos of evil spirits.