Greetings from Texas. I have two Hohner diatonic accordions, both vintage. I believe one is from the 30's the second 50's or 60's

[Basia]

 

[OuijaBoard]

Welcome, and enjoy! These are bisonoric button accordions, meaning, a single button plays two different notes--one on the push, and one on the pull. Like with a harmonica. On this site these types of button accordions are most often discussed in the forum section titled "Accordion Chat," in its subsection headed, "All Things Diatonic." It's shown on the main "All Forums" page, but here's the link:

All Things Diatonic

Another resource for information and chat about these little guys can be found at https://forum.melodeon.net/