One note on the use of blackletter in German-language print/signage: until 1945 it was standard for most official print material to appear in blackletter, a type known as Fraktur in German. You start to see more sans serif fonts appear in German-speaking countries around WWI, but it was the exception rather than the rule. After 1945 the Germans (East and West now) switched to a roman script in their print and official correspondence.

This was the case for Americans learning German, as well. When my grandmother learned German in Ohio in the 30s, she learned it in Fraktur. After I started my PhD in German at Berkeley, she gave me her old materials; it was a trip to see that everything she read was in Fraktur (which arguably is the bane of many who study this language today). Any American at the time having experience of the German language would have immediately associated Fraktur with “Germanness.” And German was an extremely popular language to teach back then.

With that in mind, it’s still not far-fetched to imagine that Mr. Matsumoto decided to employ a modified blackletter style as a subtle way of protesting his (and many others’) internment.