As to Kokugikan, I presume that views from seats are good regardless of floors, so personally I find no reason to recommend you stick to a box seat on the 1st floor.
Examples of views from seats in Ryogoku Kokugikan
(which is used for January, May and September Grand Sumo competitions)
: From box seats [
Masu seats] on the 1st floor
-
http://t.pia.jp/feature/sports/sumo/kokugikan-1f.html: From arena seats [
Isu seats] on the 2nd floor
-
http://t.pia.jp/feature/sports/sumo/kokugikan-2f.htmlOn these webpages, the east is to the left and
sho-men is around the bottom. From a
sho-men seat, you see the face of the referee [
gyouji] at the beginning of a sumo match.
In Kokugikan during a Grand Sumo competition, there are FM broadcastings in Japanese and in English with a live report of evening matches. A rental radio is available at 100 yen as a fee and 2000 yen as a deposit; the latter is refunded when you return the radio. Also a headphone is sold at 100 yen.
I requested for the best available seats for the final day of the tournament and the best seat they were able to get for me was arena seat A in row 5. A nearest box seat is not the best seat for everyone. I suppose there may well be visitors who prefer arena seats on the 2nd floor, for example to grasp better the flow of each sumo match.
Which seat is nice depends on the purpose of watching Grand Sumo matches at the site.
By the way, are you aware that a winner can be decided before the final day?
In each of Grand Sumo regular competitions (six a year), losers do not have to leave the competition. As to Maku(no)uchi division (#), the wrestler who won most of 15 matches becomes a winner of the competition. So, for example, if there is only one wrestler who won 14 matches while other wrestlers won up to 12 matches, he becomes a winner on the 14th day.
Probably one of the most attracting scenarios is that a playoff of Maku(no)uchi division (#) is held on the final day when there are multiple wrestlers (including at least one yokozuna) who won the same number of regular matches during the competition.
(#) This division is called "Makunouchi" to be exact, but often referred to as "Makuuchi."