About Kanoso-sen
Kanoso-sen is a part of shogi to review the game with the opponent player after finishing the match. This is a very interesting and useful part of shogi game because we can learn what other moves were possible during the match which could have been better not only from black player but also from white player. Then you can experience the game from both sides which improve your shogi sense for the next match.

Therefore, a good player never misses an opportunity to have a kanso-sen considering a very important part of "enjoyment" of shogi. In fact, Mr. Habu tends to take much more time for Kanso-sen than the time for the game itself.

Manners on the net
As this is a part of game (until Kanso-sen finishes, the game itself does not finish.), it is considered not polite to leave without saying anything even if you have a family matter and so on. It is rude to leave without a word especially to start a next game! Because the opponent player could have wanted to pursue other moves in Kanso-sen discussing with you.

The length of Kanso-sen is totally depending on the excitement of the game and the availability of the opponent player and YOU. If you have to leave during the Kanso-sen, please tell politely in advance before leaving. This is the same manner as in the face to face shogi match.
(In ISC official games like monthly game or international friendly match, we would recommend 15 minutes Kanso-sen as "maximum" in case there is a next match planned in the game schedule.)

Then Kanso-sen itself basically belongs to two players not to watchers but watchers can join as far as they respaec that point and try to help a positive development of Kanso-sen.