Gift Tax 1.1m yen Exemption – Timing & Do I need to notify my bank or anything?

Hey, friends. Per advice I received recently here, I'm looking into receiving an inheritance from a grandparent in smaller installments via the 1.1 million yen gift tax exemption. I've been looking into what needs to be done for a smooth experience, and I was curious if the money is wired, do people need to notify their bank here in Japan in advance that a large-ish sum is incoming? Do you have to do anything to explain to them where the money is coming from (i.e., KYC stuff) post-wire?

I also have been seeing Japanese tax accountants say to not wire the ~1.1 million yen at the same time every year, as the gifts could then be classified as "定期贈与" (regular fixed-term gifts) and therefore subject to a cumulative gift tax. Has anyone ever had any experience with that before?

I also noticed mention of "gift contracts" as being good practice, but this is more to do with concerns over personal disputes between giver and givee later down the line than a document that is necessary to prove where a gift is coming from and why, correct?

Thanks again…!