Some ideas to this "double hamon"?

[Christian]

Hi!

Since long time I have one very damaged sword in my collection that might worth nothing but is very interesting and a kind of special subject to me

It looks like an old tachi that is o-suriage (full length now is 87cm). Remains of the ken horimono are still there and the shape looks old.

The most interesting fact is the multiple hamon-line that I did not see on any other sword so far. Well, as said, the thing is in bad shape but maybe one can give me some information about this hamon effect or the sword at all?

It's not easy to take pictures from this but I try my best...

Thanks in advance! Christian

[Rivkin]

Its an interesting (and huge) piece with prominent utsuri. Boshi picture next to measuring tape would be appreciated.

[Christian]

Thank you for the fast reply. Here a picture from the boshi.

[Rivkin]

It interrupts in the most interesting place. Looks like Muromachi blade in notare, generally they get attributions to Mihara or Uda. Mihara would have stronger jigane, long kaeri (damaged here). My guess its more Uda-type. They also can have very patchy-looking and dark utsuri (antai).

[DoTanuki yokai]

The double hamon is called Nijuba but there can be triple hamon where it is then sanjuba. 
Nijuba is mostly associated with Yamato school and Uda got it roots in Yamato tradition so I think this is a good guess for what is visible. 
 

[Christian]

Perfect, that is something I can further research now. Thank you a lot for your answers and your time! I really appreciate it. 

[SteveM]

This would have been an enormous sword. Would it be possible to get close up shots of the nakago? Those horimono on the nakago should have originally been on the blade part of the sword, which means the full length you quoted of 87cms would have been close to the original cutting edge length. 

[Christian]

Yes, I think it must be more than the 87cm because the proportion should match. Attached some close ups of the nakago.

 

[PNSSHOGUN]

Often the bottom of Ken Horimono start near the original location of the Habaki....

[2devnul]

Could it be Odachi in the past? 

[Christian]

Odachi is from 90.9cm so I think this is more than possible.