The Japanese just call this particular shinai, "koban". Koban is old Japanese money used in the Edo period (1600-1868). It's shape is oval. What is koban about a shinai?
When we use the word, koban, in kendo, we usually talk about a shinai with an oval handle or tsuka.
This gives us the grip of "katana".
Unlike the round tsuka, a shinai with the koban grip gives us better cuts i.e. the angle of the blade tends to be correct.
Tsuka-Gashira of Koban
Tsuka-Gashira of Normal Shinai
With the koban, we cannot grab a shinai from the side. Well, we still can but then we quickly notice that we are grabbing the shinai wrong. It feels similar to grabbing a bokken.
These are the benefits of the koban shinai. Does the koban has disadvantages?
1. People might think that with the koban grip their cuts would be better.
Yes. It HELPS to make your grip better but it does not mean it makes your cuts better. You still have to strike with good awareness of the angle of the shinai.
2. Once a koban shinai is broken, it is hard to find a piece of a shinai for fixing the broken shinai.
Since the tsuka is oval, we just cannot use an normal shinai piece to substitute for the broken piece.
3. Due to its special shape, it is a bit pricy.
If you have not tried a koban shinai, I recommend using one. If you have a problem with your shinai rotating in your hands i.e. the blade is not facing down, then it is worth trying a koban shinai.