Japanese Knife ID help

[crockerculinary]

Hey folks!
So a gentleman came in with a couple old deba that belonged to his parents. His family is Japanese and he said they were used by them for as long as he can remember but he knows nothing beyond that. They are definitely old and interesting, but not well maintained or particularly “fine” in detail. If anyone could help ID/translate he would appreciate any info. Thanks!

 

[ojisan]

Left: 友鶴作 Tomotsuru Saku (Made by Tomotsuru)
Right: 登録 兼定 Touroku Kanesada (Registered Kanesada)

I don't find much information about Tomotsuru.
Kanesada still exists.

 

[crockerculinary]

Left: 友鶴作 Tomotsuru Saku (Made by Tomotsuru)
Right: 登録 兼定 Touroku Kanesada (Registered Kanesada)

I don't find much information about Tomotsuru.
Kanesada still exists.

Thank you very much!