Originally Posted by luvforty
how do you exactly power it with the shoulder? i think it's called arming the ball.
The same way you should use the shoulder in the forehand.
And another thing, the TOP of the grip on the 1hbh should be emphasized, Not the bottom. Specifically the knuckle on the top bevel for an eastern grip. A good one hander pulls the buttcap to the ball. You feel this pull
all along on the top bevel from your index finger, down your hand to the buttcap. If you concentrate on the bottom this will lead to tension in the hand wrist which you don't want. Loose grip is better and faster. The supination should be directed/felt along the top bevel. The leading edge, the same way concentration/emphasis is on the 4th bevel etc on a forehand with a semi-western grip.
This is another reason people use the 'pull the sword' analogy because when a samurai pulls the sword out of the sheath they pull from the TOP so that the blade (the bottom of the sword) doesn't scrape against the sheath and stays sharp. The sword is pulled out using the shoulder muscles. Not the back.