Yes, 17%, it's weak for U21 team, 28% it's more logical for NT team.
So ok, but why it's weak?
Cause Japan U21 team, it's the simpliest way for Japanese Manager to have an International player.
An All-Star potential player, is enough to reach U21 team, each team could have one or two on each draft.
A better potential will be appreciate of course, but we reserve the best potentials for the NT.
Indeed, U21 player does not train in the same way as an NT player, who requires more patience and better potential.
How many time for a U21 player?
I'm agree, one season is not enough and it depends ot its skills and of his age, 18 or 19.
Depending on his age, 1 to 2 seasons of 1 on 1 AS/AF then 2 seasons to increase the primaries according to his position.
In fact until the end of his 21 years, that is to say 3 to 4 seasons.
I'm not coming to sue anyone, BB remains a game where everyone is free to play as they see fit.
I'm here to show what is the real interest in training national players.