Junior training balls are grouped into three stages by bounce speed. The higher the stage number, the slower the ball and the easier it is to hit, so children can practise a correct swing at a speed that suits their height and strength.
KYUYUU offers three models. CH-JUNBL-STAGE3 measures 72–75 mm, a larger ball for players who are just starting. CH-JUNBL-STAGE2 and CH-JUNBL-STAGE1 both measure 63.5–65 mm, the same as a standard ball, and bridge the way to regular play.
Start at Stage 3 and move to Stage 2 and Stage 1 as skills improve. Schools, clubs and coaching programs usually keep several stages in stock.