I am always a little reluctant to put dates on mandaus.
However, mandaus of similar style and craftmanship are depicted in a Swiss book : "Aufschlussreiches Borneo, Der Geologe Wolfgang Leopold in Niederländisch-Indien 1921-1927" (Zürich 2011)
So this mandau could date to pre ww2.
Best regards,
Willem
PS, this one is better than those in the book. especially the scabbard
