Japanese Stamps With Unexpected Cancellations

Going thru a recently acquired box lot, I came across this Japanese block (of 8) of the 10s imperforate sun & dragonfly issue of 1923, Scott 186.

Of note is that this Japanese multiple is cancelled by six 1924 Vancouver, B.C., Canada circular date stamps.

The only explanation that comes to my mind is that these were Canadian arrival markings that were applied to the block of stamps, albeit from Japan, that hadn't been cancelled yet. Is this a reasonable assumption, or is there a "juicier" explanation ?

Normally, postal workers would not cancel stamps of other countries.

My guess/thought is that this is from paquebot mail. A ship of Japanese registration would and could use Japanese stamps for mail posted on board. With no post office on board a passenger or cargo ship, mail would be then be passed on to the port of arrival's post office and get cancelled there for onward carriage to its destination. A paquebot marking would appear on a cover but we don't have that available here.

hy,
Your explanation is way juicier than mine and makes perfect sense. Thanks much for posting it !

I agree with hy as Vancouver was a not uncommon cancel on paquebot mail. Also I note that whatever item these were on, it must have weighed quite a bit as the single international rate was 10s (if I recall correctly) and these total 80s.