Collectors call the two versions the VZ23 Long and VZ23 short respectively.
Some refer to the short as the 98/22, but I have taken this as the designation of the Mannlicher bayonet.
Here are some links that will help you out on your adventures finding Japanese bayonets.
As World War 2 pushed on, the Japanese bayonet quality control rapidly deteriorated and the bayonet was modified to save resources.
It is thought that when necessary the Czech's supplied the Belgians with weapons to help complete orders, even though they were in direct competition for the same contracts.
This further complicates the identification of users etc.
Knowing the good from the really good is often a matter of identifying the various markings.
One of the more commonly known Japanese bayonets is called the Type 30 Arisaka or 30th Year bayonet.
The differences come from the variations of cross guards , pommels and grips as well as the various arsenals who built them.