The students work in groups and try to decide whether to use which or that. One member comes up with their answer. After everyone has brought their answer do an answer check.
As for which one to use I looked it up online and I came up with this rule.
Use 'that' when the information distinguishes the objject from other objects. 'I live in the house that has a green door' means the other houses don't have green doors. Use which when you are providing additional information but not identifying information. 'I live in a house which has a green door' means other houses might also have green doors.
Well, I think that's the way it works.
Honestly this point isn't really worth teaching at this grade level and I try to avoid it unless pressed.
I'd follow this up with a writing activity where the students discribe things visitors might find interesting in Japan. Maybe use a rule where one sentence must use a relative clause.
I feel like more than "which" and "that" in these sentences, the determining factor for if the object is distigushable from others or not is the use of "a" or "the."
According to https://www.grammarly.com/blog/which-vs-that/.
"that" is a restrictive clause
"which" is a nonrestrictive clause
If the additional information is not needed to understand the main point of the sentence you use "which", but if you're talking about something specific, you use "that".
"I live in the house that has a green door" - you're identifying something specific
"I live in the house, which has a green door, down the street" - you're adding information.