The Way of Sumou
Sumoudou is the Way of Sumou. It is the embodiment of moral and ethical values that Sumou as a way embodies.
Sumoudou is the realization of the underlying principles of Sumou.
What is the underlying principle of Sumou? It is the understanding that Value is derived from Fighting for attaining your Goals. The Goals of Sumou are to Prove Yourself, to demonstrate that you possess Superior Power via which you demolish your Opponent. It's very simple. Yet this simple objective is very hard to achieve, since it is very hard to Fight on Power against an Enemy whom you recognize to be stronger.
For Little People this is impossible and so they resort to Trickery, trying to trip the Opponent and make him stumble and lose Balance.
But that is completely worthless. Why? Sumou is Chikarakurabe and nothing else. That's why in Sumou Value comes only from Power Sumou and nothing else. If your Opponent falls because you jumped aside rather than Fight him, you have achieved nothing. You Win but you fail in what you should do - Prove Yourself.
Because Sumoudou is so simple yet hard, it leads to Enlightenment.
It's very easy to be a Hero when your Opponent is weak, that's no Achievement. But when you know you are not strong enough, that's when a true Hero shows. Only if you can Fight on Power when odds are against you can you achieve something heroic. This is Sumoudou.
The core of Sumoudou and its embodiment is Keiko.
The realization and testing mechanism of the reality of Sumoudou is Shoubu.
Sumoudou dictates how a Rikishi must fight, you must strive to act right. Acting right means always doing the right thing, doing Good Sumou.
Probably the most famous strict adherent to the Way was Yokodzuna Futabayama, some of the Ideals of Sumou he expressed in his Japan Sumoudou Rikishi Charter.
Current Rikishi health rules set down by the Nihon Sumou Kyoukai are also a bit influenced by the ideals of working diligently without regard to personal gain or comfort.
Sumoudou is present strongly, albeit only verbally in Yokodzuna and Oozeki Koujou - their Promotion acceptance speeches.
Finally, Sumoudou's verbal tradition is alive in Sumou Sayings.