Handcuffing an opponent on the inside?...getting either the angle to attack while not being countered...or by being slick enough to use hand placement/grappling (within the rules) to block an opponent while scoring themselves... Prime examples Ezzard Charles holding Joe Louis' arms inside, then getting off quick one-two's, then moving out of harm's way...Seeing a picture of Benny Leonard placing his left hand on an opponent's right arm to take it away in close range... Who catches your attention?
Dang, I've seen many but the one who stands out here is Jack Johnson. This skill was made to order for his style and strength.