Unidentified coin

Can you assist with identification of this coin? I've got quite a few. Also, what would you estimate the grade to be?

Japan. I have quite a few of these coins also. Will decide which of these three it is shortly ...

https://en.numista.com/catalogue/pieces7515.html
https://en.numista.com/catalogue/pieces922.html
https://en.numista.com/catalogue/pieces3047.html

It's Showa year 46.

https://en.numista.com/catalogue/pieces922.html

Thanks a million! At least I know where they are from! I'm going to have a hard time dating them all though... how do you identify the dates?

https://en.numista.com/numisdoc/calendar-japanese-34.html

At the top of this page are  Home  Forum  Numisdoc
It is in Numisdoc, in the  Dates & calendars  part.

P.S. I have created an illustration showing how it is calculated. On the page first type in the Emperor on the keyboard (my illustration below shows what I typed in on the left). Then click on the Japanese number characters themselves - not the Western numbers; there could be one or two or three of them. Lastly click on the Year character - which will then display on the right (like in my illustration) what the date is.

Thanks! That's fantastic! It'll be fun to date all of these coins now...