[YuriTokoro]

Originally Posted by Nathan

I would modify it even further:
It is held around August 15 across Japan.

"Across Japan" means that the festival is celebrated in many different places in Japan.

Hi, Nathan. Thank you very much.
“Across Japan” sounds very useful.
However, my dictionary says, “When something happens across a place or organization, it happens equally everywhere within it.” Some areas in Japan don’t have bon around August 15. That depends on the area. Don’t I have to be concerned about “equally everywhere”?

The main custom of Obon is visiting the graves of our ancestors, but after that it depends on the area.

When we make a horse and a cow before we visit the graves, can I say “after that”?
Should I say “other customs”?

We know that a horse is fast, and that cows are slow, so you can leave that information out.

I see. I hadn’t known that cows were slow, before I started writing this post and read Wikipedia. Most Japanese people make the horses and the cows without knowing cows are slow. Meanwhile, you know it. I see.

I would write these two sentences like this:
The cucumber, representing the horse, is used by the spirits to arrive quickly. The eggplant, representing the cow, slows the spirits' return to the afterworld. This lets the spirits maximize their time with us.

Thank you! This is what I wanted to say.

"and they think it’s very good opportunity" could be rewritten:
and they take advantage of this opportunity.

“They take advantage of this opportunity.” Sounds exactly. Thank you.

You should avoid coming to Japan during Bon.

There are many expressions I don’t know. Thank you, Nathan.