Before you do that you will have to solve the dragon costume puzzle, before you solve the dragon costume puzzle you would need to go talk to the man writing a haiku near the far west(left). Anyways, after you solve the puzzle the police will will give you something and tell you to take it to the sumo match place.
The champion sumo (Yokozuna) is inside the sumo match place.
you go to the sumo match with the card the soldier gives you
You go help villagers or go to the sumo match.
By clicking first after the man say began.
The island that has sumo-wrestling in it is the Red Dragon.
you have to win the sumo wrestling match and when you do the sumo wrestler will get mad and Basho will save you. then he will say that you can come to his cottage to train with him.
In the Sumo Wrestling match. Talk to the guy there and you'll give him the betting slip.
There is no "Sumo Island." The island that features ancient Japan and a sumo challenge is Red Dragon Island. (see the related question)
You don't have to open it. It is open already, and you could just go in.
You train at the Lake House (far left) but only after you beat the Yokozuna at the sumo match.
you cant
in the West Edo