Mixing Japanese and western characters is always tricky. Japanese fonts do include roman characters but they are never as well drawn as those of the classic western fonts, so what you tend to do is to mix fonts, trying to find a good match.

The most popular Japanese fonts for use in conjunction with Helvetica are probably Gothic MB101, Midashi Go MB31 and occasionally Chu Gothic BBB, all by the Morisawa font foundry. I would have to eliminate Chu Gothic BBB from the mix right away though as it is only available in one weight. This is true of Midashi Go MB31 too, but in this case it is the more useful bold weight as opposed to the regular, which I rarely use.

An alternative would be Kozuka Gothic which is included in Adobe’s Creative Suites. The roman characters don’t have much in common with Helvetica, but the Japanese characters are good. The same thing could be said of the AXIS font which is really nice overall, with a good balance between Japanese and roman characters – the roman ones again having little in common with Helvetica however.

In the end there is no right choice, it all comes down to taste, but I will follow up with a more detailed comparison in another post.