I have bought one of these Buttafly Yoga Seats to work on my posture out side of the karate dojo.
Whilst karate stances and techniques exist at the point of when they are executed, your posture is 24*7*365 - every second of the day. Many of us work on computers at a desk and use our mobile phones far too often, which can only lead to issue long term.
Even though through my karate training I am more body aware of tension and stretch in the body, I don't spend enough time working on it at home and at work.
I will see how this goes and report back in the future.