I WOULD ESTIMATE THIS DAGGER WAS COLLECTED WW2 OR AFTER LIKELY WHEN WE HAD TROOPS THERE POST WW2. I HAD ONE THAT BELONGED TO GENERAL EISENHOWER'S PHYSICIAN I GOT AT HIS ESTATE AUCTION YEARS AGO. THERE WERE PICTURES OF IT ON THE FORUM BUT I DID NOT FIND THEM.THIS EXAMPLE IS CONSTRUCTED CORRECTLY AND OF THE PROPER SIZE AND HAS THE OPEN SLIT THAT IS A TRADITIONAL AINU DESIGN. I POSTED MY DAGGER ON THE FORUM AND GOT A IDENTIFICATION AND RECEIVED A INQUIRY AND OFFER AND SOLD IT TO A TEACHER WHO COLLECTED THEM BUT UNFORTUNATELY HE NEVER SHARED HIS COLLECTION AND INFORMATION ON THE FORUM.
THIS KIND OF WOOD DOES NOT PATINATE QUICKLY AND IS FAIRLY HARD SO AGE IS DIFFICULT TO TELL ESPECIALLY IF IT WAS BOUGHT NEW AND NEVER USED. HERE ARE A FEW AINU PICTURES. 3 DIFFERENT KNIVES ONE SWORD AND SOME PICTURES. I HAVEN'T SEEN MANY AND THEY MAY BE MOSTLY A WORK KNIFE BUT THEY ARE INTERESTING.