Here are four Japanese wines that I tried recently. They are all from Nagano.

First, the white on the right (Sunsun Niagara 2017): I approached this one very suspiciously, since I never found convincing wines made from Niagara (it is not even a vinifera grape variety).
On the nose I was very surprised: grapey, very grapey, even more grapey than a Muscat wine. Just nosing it seemed like biting a muscat grape. Good intensity, but not overwhelming. True, there is not much other than the fruit (peach, apple peel), but the palate is nice: completely dry (which is not always true in Japan, as many wines tend to be sweetish), good acidity. Fresh and light. I could even give a 1.500 yen for this one.
Let’s see: 1,200 yen. Not bad. If you like this kind of very aromatic wines I can recommend it.

Next, the Musée du Vin Chardonnay 2017. Japanese winemakers are trying again and again to do something decent with the international grapes, because they have appeal to the public.
This one is not the worst I ever had. In fact it is pretty decent. Not very intense, but still there is some white apple pulp, melon, peach, even a light yeast character from (I suspect) some time spent on lees. Rounder mouthfeel than the first but still on the light-medium side. Fresh acidity and dry. For this one I may go up to 2,000 yen maybe.
It is 1,800 yen. Good.

The reds are always a problem in Japan because the structure is much more important and most japanese red wines fall flat.
This one, a Merlot-Syrah blend from the same winery of the previous Niagara, is no exception. Aromas are nice, red fruits, a bit of peppery spice, with a touch vanilla in the aftertaste (though the technical data do not mention oak, so I could wrong or maybe they used oak chips/staves). However the body is light and the tannic grip almost absent. It is not sweet, for which I am really grateful, but it lacks weight on the mid palate. For me this is no more than 1,500 yen, to be generous. And the price is: 2,000 yen without taxes. 
Uhmmmmmmmm.

Finally the Pinot Noir from Villa d’Est 2016. I like Pinot Noir and I liked this one.
It is quite peculiar, nicely intense and spicy, with cinnamon and cloves in particular. I find also bright red fruit, rose and light vanilla character (the latter after some aeration). Pretty good structure, more or less what I expect from a Pinot Noir. Supple tannins and medium body, but still more tightly knit than the previous Sunsun. I am a bit puzzled by its garnet color, especially because it is under screwcap, so not much oxidation should have happened in bottle. But I am not complaining.
I would buy this one for me, but at what price? Now let’s get pragmatic: if you go up to 3,000 yen you start invading the field of Bourgogne AOC wines and it becomes difficult to compete. Since this is good I would even give 3,000 yen maybe, but tax included.
Let’s see the right price: over 5,000 yen. 
This won’t do. I am aware that making good wine in Japan is not easy, but for such a price I can find some decent Burgundy (minor) village or quite good Etna Rosso or Chianti Rufina. Hell, even a Taurasi Radici from Mastroberardino is cheaper! I know, that’s a different style from a different Country, but still! What will happen when, next year, the custom tax for European wines will be lifted?

Japanese producers can make good wine, they are not stupid, but from a marketing point of view a European wine can easily beat a Japanese one. When you buy a bottle of wine from France or Italy (but I would say even California or New Zealand), you also get a kind of “immaterial experience”: you are enjoying a piece of a distant land. This is pleasant and it evokes pleasant images. Japanese wines cannot offer such imagery.
The whites here got it right, with a reasonable price for their quality, the reds less so.

The best move for Japanese producers is to find a sweet spot for their product: the more basic ones, like the first three are ok in the 1,000-2,000 band, but the exact position should be carefully decided (the Sunsun red is overpriced). The better ones, like the Pinot Noir from Villa d’Est here, should be in the 2,000-3,000 yen range to stimulate people’s curiosity.
Anything above this and you are condemned to remain a very small niche market, running the risks, next year, of being wiped out by European wines, finally free of custom taxes.