Bronislaw Piotr Pilsudski 1900 ca) An old Ainu woman who lives among the Olts in the Amurlande near Murjinsk [Eine alte Ainufrau, die im Amurlande in der Nähe von Murjinsk unter den Oltschen lebt]
Oltscha, Oltschen, Ultschen, before Mangunen, are a small ethnic group in Siberia. They lived on hunting and fishing. It seems that Ultschen/Oltschen (in German) is the appropriate naming today; English: Oltcha.
I'm indebted to Margit Z. Krpata for proving this information (2 August 2018).
