Connecting unknown ancestor to family tree
I am in a bit of a dilemma with my family history work. I was going through my recent changes to some of my ancestors. I noticed some of the typical things that happen like my cousin adding memories to my great-grandfather's life story and other recent attachments to my ancestors. When I stumbled upon an ancestor whose name was in Japanese characters. To my knowledge, I do not have any Japanese heritage. Curious I clicked on his profile and tried to see my relationship with him. Unfortunately, they told me that our common ancestor is more than 15 generations. I did notice that Seitoku (my ancestor) died in Peru which I know I have family from. The only other information that I have is the birthday and death day of Seitoku, his spouse, and their 6 children. One of their sons is married and I have the son's wife's parents and grandparents.
When I go to look for sources on Family Search and Ancestry, it does not come up with much. My thought was to find Seitoku's parents and then start building the tree up until I find an ancestor or a last name that I recognize. The only issue that I have is trying to find documents that I can say for sure are connected to Seitoku and/or his family. Are there any archives such as immigration records, births, or marriages from Japan that Family Search has that I can specifically search?
If anyone has experience or guidance for me it would be much appreciated.