Thanks for all the replies (far too many to reply to individually). The
consensus seems to be that Kunou will last a few seconds, unless one of
the following happens:

1 Ryouga gets lost, either before or during the fight.
2 Ryouga is wearing a watermelon (but check below).
3 Ryouga gets lost and Kunou chases Ryouga
  off into the sunset (literally). spamfic anyone?
4 Kunou gets a lucky strike with his stick on a
  vital spot. (its actually a bokutou I know...)
5 Ryouga gets wet.
6 Ryouga falls victim to the dreaded 'plot device'.
7 Kunou benefits from a 'deus ex machina'.

note, in the time frame I am using for this fight, neither has yet been
known to receive any special training, so watermelons and breaking point
and shishihokodan are not yet factors.

---
Rhialto
zenkai tte yokunai ne?