ROKUJURO

This groove has no technical purpose in my opinion. Might be just a mistake by an amateur who was going to cut it too short, but after rethinking, decided otherwise.

Rob, animal skin would not be too exotic; I have seen a number of these besides the standard SAME (pearl ray skin). Shark-skin can even be found on WWII Navy sword SAYA. Shortening a blade may leave a mark on the NAKAGO, though on the (slightly out of focus) photo you provided it is not visible to me. A reason for shortening might have been to be allowed to carry it as a merchant. Only SAMURAI were allowed to carry blades of KATANA size.

John, don't you think that this kind of TSUKA would be more typical for a so-called 'Merchant's' KOSHIRAE? Late EDO? If the blade was WAKIZASHI NAGASA, I would guess so. Of course it does look thrown together with the glue coming out under the MENUKI. Not beautiful....

The TSUKA cover looks like Iguana or lizard skin, or maybe a special shark skin type. I am with Piers on the TSUBA; it is probably amateur work, the SEPPA as well.

Blueblue, please sign all posts with at least a first name plus an initial, so we can address you politely. You can also show your name in your profile. This is requested here on the NMB forum.

EDO JIDAI = EDO era/period. There are different opinions on the span of time, some say 1596 to 1876 (or 1868), other see the start with KEICHÔ era (1614). In literature, you may also find 1600/1603 to 1868 or 1876 (HAITÔREI, the end of the SAMURAI era)

Rob, usually there is no patination involved in swords. The patina builds up on the NAKAGO by time and use. This blade has a drilled MEKUGI-ANA. The even red rust on the NAKAGO is not deep, and the polish on the blade is not "profound" so I cannot see HADA (at least not with these images). It was stored in a damp place and thus damaged by recent (heavy) rust. My guess would also be very late EDO JIDAI, but in the end, it is quality that counts, and preservation condition. Age by itself does not hold much value.

Try without doping, it should work!

Vincent, I could not find KEISHA period. You probably meant to write 慶長 KEICHÔ (1596 -1614) which is the time when NANKI SHIGEKUNI worked.

Another video about Johan:

Shane, as this is not a NIHONTO, it should appear in the military section of the board.

Maybe an agent such as Kelly Schmidt could help?

Chris, obviously, the KANJI are similar but the script is different in my eyes. By the way, YASUMITSU is not a rare name among swordsmiths. Also, the shape of the NAKAGO is completely different so very likely another YASUMITSU.

https://auctions.yahoo.co.jp/jp/auction/d1206571515 https://auctions.yahoo.co.jp/jp/auction/l1214130896 https://auctions.yahoo.co.jp/jp/auction/c1214142948 https://auctions.yahoo.co.jp/jp/auction/1214173253 EBIRA are for war shooting, so I guess you are practicing HEKI RYU INSAI-HA?