I clicked your link, and I think I see the problem- the item's not sold by Amazon, it's coming from a third party seller. Scrolling through the various options, you can find Amazon proper, but it's marked 'currently unavailable'.
Third party sellers usually don't ship internationally, even ones with their orders fulfilled by Amazon. My handful of Amazon.jp orders have been looking for retro items that are difficult and/or far more expensive from Ebay. Buying anything always starts with 'dump all possibly affordable copies into cart, see if any stick around at the shipping step'. Usually everything gets kicked out & I try again a few weeks later.
I checked the sellers I've used previously, none of them are selling this game. You're either going to have to wait for Amazon proper to re-stock, or start trying random sellers to see if someone will ship internationally.