Description from the Glenbow:
There's a LOT of theorizing about that photo. Was it some sort of trade item? A leftover from Chinese exploration? Evidence of time travel?
And with a name like "Dog Child", I wonder if he truly was a son of a #####.
No one knows. It's fun to hypothesize, though...
If it was taken in the 1890s by a photographer from Vancouver, it could be just a prop the photographer inserted to make the photo more interesting. Some photographers enjoyed playing around with props, retouching, double exposures etc. in those days, just as some people enjoy photoshopping their digital images now.
On the other hand, knowing the Indian love of prestige weapons, someone may have given it to him for some reason, knowing that it would appeal to him. There was a store selling imported Japanese goods in Victoria BC in the 1890s. The owner was the first Japanese immigrant to Canada, Nagano Manzo. He sold all kinds of Japanese items, maybe swords too.
More likely something brought back by one of the thousands of British and European visitors who flooded into Japan after 1868. After the CPR was completed those people usually came by train to Vancouver, then CPR steamship to Yokohama. When the Samurai were forbidden to wear swords there were plenty available for sale to foreigners. For a time the Japanese turned their backs on many of their feudal symbols and the samurai were never very popular with the common people, especially with the merchant class who they used to extort non-repayable "loans" from. The merchants who were also at the bottom of the Edo period hierarchy, below even the peasants, would have enjoyed buying up swords from impoverished samurai who had lost their rice stipends and occupations and needed money, as many did.
There were lots of foreign traders exporting all kinds of Japanese goods and art objects in the late 1800s too. Remember how the wood block prints took Europe by storm and inspired the Impressionists, so we're told.
The interesting question would be where is it now?