Ok, so here is where I am going with this one. The first time I saw this post, I focused on the name written on the back of the canvas. And, like Ipcress, I came up with abstract art.
But, when I blew up the bottom right side of your painting, I thought (just thought) there was a signature so I concentrated on that only.
I'm thinking that your artist is actually Saburo Shimada; not Hiroyshi Shimada. And if I only saw this once, I would have said, "that's weird". But when I saw it twice, I said "hmmm".
Here's the first listing:
http://www.ebay.com/itm/like/282774398893?vectorid=229466&item=282774398893&rmvSB=trueLook familiar?
And, the second listing which explains the gallery confused Saburo with Hiroyshi:
https://www.ebay.com/itm/Saburo-Shimada-Paris-view-by-River-Seine-c1981-/252796593318So please take a second look at the signature....