The armour in the picture doesn't look like the scale or lamellar armours that were the commonly seen characteristics of east Asian armours, such as those in Japan. Whilst these types of armours almost always incorporated leather in some way, whether as a backing for the solid metal plates to be secured on to, or as some other form of securing (for example, with lamellar armour, leather was used to tie together the plates of metal). Whilst it could be possible that large pieces of leather could be used as torso protection, the Japanese had access to metals and, despite its quality, smiths were still very much able to craft suitable scale/lamellar armours from it.

Unfortunately, that picture has a really low resolution and I can't find any higher resolution of the full armour, however I found this image of his armour - the armour looks to just be designed to appear as if it had many small individual pieces, but it really is just a single leather-piece armour, which was not common at all (note - not common, not necessarily non-existent).

I would argue that it's not even armour - /u/bigbluepanda's photo shows it folding and far too thin to be really effective. Leather armour was generally stiff and thick, and even buff-coats, while less stiff, were fairly thick - between 2mm and 6mm, on average. This looks to be more of a surcoat or tabard, and the 'real' armour would be the super fine "mail" underneath, assuming that's what the knitted material is.