|A 17th Century illustration: Koxinga (r) sentencing Hambroek to death|
from 風中之葉：福爾摩沙見聞錄 by Lambert van der Aalsvoort
Since the names of Koxinga's generals spelled in Dutch were based on Hokkien, the latter was probably the language used by Koxinga in daily conversation (in addition to Mandarin官話 and Japanese).
Perhaps the most interesting aspect is that Meij saw a bearded Koxinga that seems to confirm that portrayed in paintings commissioned (allegedly) soon before his death in 1662. In the Cheng Family tradition, men are always clean-shaven and mustaches/beards are kept only when in mourning of parental deaths. It now appears that Koxinga was still remembering his mother Lady Wen's untimely demise.
|Koxinga playing Go (artist unknown)|