Budbreak

BUDBREAK The point at which a bud has opened enough to show a green tip.
BUDBURST The point at which a buds contents unfurl (the new leaves appear). ...

Budbreak on Old Wood
It is true that A. palmatum will sometimes sprout from adventitious buds (dormant buds between the internodes), but it has a very strong predisposition to bud out only at the nodes.

After budbreak, pinch all apical buds with the exception of one that will become the sapdrawer.
The sapdrawer will be used to 'soak up' the excess energy of the tree and protect the other branches from developing long internodes.

See also: Plant, Japanese, Growing, Bonsai, Bark