Appropriate Age and/or Rank

[Evil Dave]

I do believe that a knowledge in the basics are needed before weapons training begins. Although in my opinion, most places wait too long, blue or purple belt {5th, 4th kyu}. The student does need a good foundation in stances, kicks {mainly for body control and balance}, blocks and strikes

[again mainly for targeting purposes, they now know where they are supposed to be hitting}. Not necessarily kata, as they will be learning new and different kata with the various weapons. I would start my students around orange belt {8th kyu}.

Even in various Army's Basic Training, the new recruits are not handed a weapon on day one. Usually the rifle comes along in week 2 - 4 depending upon the Army's training plan.