I always enjoyed watching sumo from when I was a small kid. I always wanted to watch it live. This time, I learned about when they have sumo and had the opportunity to go! I wanted to tell you that I personally thought it was AWESOME! Some tips if you want to watch it live is:
1) The tournaments are only 6 times a year, so pay attention to when and where
2) Sumo tournaments are two weeks long (14 days)
3) Buy tickets early. They sell out fast. BUT if you miss out on reserved tickets they sell around 400 tickets per day, on the day of. (they are cheap but only the very top row)
4) If you do buy the day of tickets, GO EARLY. I went Sunday(halfway through the tournament) and got there at 6:50 am, and they weren't even letting people stand in line. So, I went there at the same time on Wednesday and was able to get a ticket. The rules are you wait in line and get a number to buy the tickets, (and NOTE: you must stay in line, and can't have someone save your spot, like if you are in a group for example)
5) IF you don't have a reserved seat, then go EARLY and try to get the main side. (the have main side, opposite side, West, and East), so go early and save that seat! (Also note, that if you get the day of tickets, you only are allowed ONE re-entry) so you can leave and come back but only once.