I'm planning on collecting Japanese coins by type, starting from the Meiji Restoration. For example, I will be collecting a 1 yen coin from all eras such as the Meiji, Taisho, Showa, Heisei and the most recent, Reiwa. I understand that the 1 yen coin during the last 3 eras has the same design, but I do want to collect them, not by year but by type.
I have read the Numisdoc on Japan. Is there anything else I need to know before I start?