Originally Posted by
RichardInSF
As I recall, the significant majority of the seats are bleacher seats surrounding the ring on all four sides. This arena is not purpose-built for sumo and is only in use for that purpose two weeks each year, so they don't do anything permanent.
This is not correct. OP, the majority of the seats ("box seats") are cushions on top of tatami mats and are not "western-style." The individual reserved seats are the bleacher or western-style seats. These are in the upper part of the gymnasium and are really bad for viewing from, aka nosebleeds.
Look at this map:
Link
I've been to this Nagoya basho a couple of times and had good seats. You should get as close to the action as possible so you can hear bodies hitting against each other. I don't go to sporting events unless they are good seats - I dont want to waste my time or money and think it is a hassle to go watch a sporting event from subpar seats. I don't know what your budget or preference is so you should make your own decision.
The seating arrangement looks like this:
http://www.bmdailey.com/JapanLife/Sumo.htm
As you can see, most of it is washiki style, not western style.
If you have three people, you will have to get a box for four people.
Regarding transportation, I'm going to echo that you can do a day trip if you have the bullet train. Also, you don't need to watch the whole tournament. Many skip the earlier sections.