Hi mc123455678
I have the following:
Credit Card Enable Status - VISA 1
Credit Card Enable Status - MasterCard 1 Info
Credit Card Enable Status - AmericanExpress 1 Info
Credit Card Enable Status - Diners Club 1 Info
Credit Card Enable Status - Discover Card 1 Info
Credit Card Enable Status - JCB 1 Info
Credit Card Enable Status - AUSTRALIAN BANKCARD 0 Info
Credit Card Enable Status - SOLO 0 Info
Credit Card Enable Status - Debit 0 Info
Credit Card Enable Status - Maestro 0 Info
Credit Card Enabled - Show on Payment 2 Info
Square confirmed that this restriction in the E-Commerce API is for Japan, specifically when creating a Square account in Japan. And that it might be elsewhere too.
Therefore the only cards capable of being used with the web input method (typing in the card information) are VISA, MasterCard, and American Express.

They say that use of JCB, Diner's Club, and Discover Card can be accomplished using the invoice method, which I understand is quite a bit more expensive to use.
English:
1. https://squareup.com/help/us/en/arti...nvoices-online
Fee seems to be 2.9% + 30c
for Card on File 3.5% + 15c
2. https://squareup.com/help/us/en/arti...es-with-square

Japanese (different conditions):
1. https://squareup.com/help/jp/ja/arti...nvoices-online
Fee seems to be 3.25% (JCB 3.95%)
for Card on File 3.75% (JCB 3.95% [same as standard fee])
2. https://squareup.com/help/jp/ja/arti...es-with-square
Has a note at the top stating that support for JCB, Diner's Club, Discover Card depends on the shop (presumably whether the application has been approved).

So Square clearly operates differently in different regions/countries.