Sumo wrestling was a shinto ceremony to entertain gods. It was believed that if the gods are not pleased, they would not bring a good harvest season.
The sumo stage, dohyo, has been considered very sacred. That is why there is a roof dressed by the purple curtains and tassels that represent the roof of a shinto shrine. In the past there were 4 poles carrying the roof but recently the tassels are used instead of poles where each tassle represents one the 4 major gods. The dohyo is covered by sand and the sumo wrestlers throw a pinch of salt to the stage, both of which represent purity in shintoism.
Before the wrestlers start taking on each other there is a dohyo entering ceremony lead by a shinto priest wearing white robes. Also before the ceremony some chestnuts and cuttle fish are placed inside the ring to be presented to shinto gods. The Yokozuna (champion sumo wrestler) wears white zigzag shaped strips of paper, exactly the same with the rice papers hanging at the entrance of shinto shrines. The wrestlers stop open their legs wide and stomp, this is to scare the demons that may be on or around the stage. The salt thrown on the stage is also commonly placed at the entrance of the buildings to ward of evil spirits.
During the entering ceremony the sumo wrestlers wear decorative aprons called mawashi. The lowest ranked enters the ring first and the highest ranking enters the last just like other Japanese ceremonies. At the end the rikishi (sumo wrestlers) hold each others hand and hold up their aprons this is an old samurai tradition to show that they are unarmed. The fringes of the ropes hanging from the belt symbolize the purified ropes in front of Shinto shrines that must always be in odd numbers (usually 17, 19 or 21 ) that are lucky in Shintoism.