Good evening kai, lee,
Thank's for your help !
I totaly agree with the restoration of a blade but some time I prefer to wait other view before making an irréversible mistake. No blade in my collection have rust.... this is just, I find, disrespectful for the Smith, the original owner, ans the blade itself.
I've tried electrolytic removal when I was in high school

it work Nice ad not really tard tout realised.
Interesting way for the kikuchi-yari ! Unfortunately I haven't this book.... But if you need other picts or measurement tell me it !
Best regards,
Clement