My eyes latched on to the fact that you, too, tell with sign-language. I know that English sign differs from American, but I suspect the Japanese sign to have many differences. My older daughter loves to collect the many ways sign changes internationally.
The most difficult thing for me about English sign is the fingerspelling differences! I was going to teach ways to use signing with storytelling & puppetry (see the photo of the tiger on my page), but the class didn't get enough enrollment. The class would have been in Canada for people preparing for deaf ministry in the U.K. Fingerspelling would have meant a major transition for me.
Don't know if there are others here using sign language, but it's worth checking.
Glad you're here & look forward to seeing more from you.