FWIW, I think a notary signature in the US costs like $4. If verification is the only problem that blockchain solves, it's not a very cost-effective solution.
I recently paid ~$150 for an hour's worth of notary services in Canada while preparing a property sale.
I guess I should have driven to Maine.
For me, a US notary signature currently involved a 2 month wait time at the US embassy. At the notary I used back in San Francisco, it cost $30, not including the cost of going there.
You can go into any bank and get a document notarized for free or a few dollars.
Thank! You seem really knowledgeable about the services provided by Japanese banks.