Congratulations, 6th graders!!
In Japan, the school year beings in April and ends in March of the following year. Elementary schools in Japan includes grades one to six. The schools that I work at all have the same graduation date, so I was only able to attend it at one school.
I personally think graduations done in Japan are better than those held in the states. It definitely feels like a large family. The lower grades (1-5) give their sempai (upperclassmen) messages, artwork and various other things. The day before graduation, the 5th graders decorate the 6th graders' classrooms (I helped out too!)
The 6th graders that graduated at this school were a great bunch of kids. I wish them all the best in junior high school!