Recently, Motoki KURODA has pointed out that the idea that Soun was 88 years old at the time of his death comes from a family tree created in the mid-Edo Period, and that such data does not exist in documents from the early Edo Period.
近年になって黒田基樹は享年88は江戸時代中期以降の系図類から出たものであり江戸時代前期の史料には存在しないことを明らかにした。