The Inugami Family - 1976 - 7/10
AKA - Inugami-ke No Ichizoku // 犬神家の一族[

Family assembles around the patriarch as he rattles his way to the reaper.
Several greedy descendants, one last will and legacy, one lone heir.
Even before the reading, one of the attorneys is murdered.
As is ever the case, there is always another lawyer.
After the codicils and stipulations are read, the killings increase.
This film contains odd characters, and odder goings on.
So much so, that midway I paused to research to see if this was based on a Rampo story.
No, but the story would easily fit into his world.