It was an interesting cutting day for the junior high school students. Many missed class so we had extra goza left and I let some of the lower ranked students attempt it -- only those who have demonstrated some degree of control.
It's not a surprise to me but the first time cutting is either a positive or negative surprise to people. The three new first timers have been in the class for different periods of time. Two have been there for almost two years now and one is in their second semester. Time itself is not enough as they found out. But angle (tachisuji and hasuji) were bigger problems. Then finally, it was a matter of speed/power.
All the basic workout practice we do with makko-giri, kesa, etc. can become boring but it takes a lot of time before you can swing it fast enough. Remember these are fairly young folks and not all have the strength to even swing with much power. One was not fast enough to cut effectively, and got stuck in the half goza.
Some of this may be because they are still unsure or afraid of swinging the sword too hard. A common fear is loosing the sword as you swing it because you don't know if you have enough control on it. That's true enough, but that's why you need to practice swinging hard and fast on the bokken.
When you switch to the katana, the extra weight makes it more cumbersome, but your grip on the weapon needs to be the same. Most bokkens have smooth handles or no wrappings, whereas katanas do. So, you get extra grip with the katana in addition to the weight, even while the bokken is lighter.
Hopefully everyone had fun nonetheless. The first cutting experience tends to be memorable at that age.