Sometimes a session, or a certain part of it, can be tiring, physically, mentally and both, and at that time it's good go down a gear, back to something low impact and familiar, like sinawalli or chi sao.
Of course chi sao sparring can also be all out and feel like a boxing match, just as grappling newaza can either feel like an all out war, like wrestling or cage, or can be as relaxed as a chi sao roll.
And of course chi sao can be demanding mentally when learning a new move and trying to get it to work.
As we did development in kempo and thai and also guard newaza the chi sao was a break as well as maintenance for that phase.
