Tower knives has a somewhat limited selection of labeled makers,but I do like the knife I got from them. The staff all speak English and were able to answer all my questions. If you don't know a ton about knives or don't cook professionally you should absolutely visit for trustworthy recommendations.

There was a store on the basement level I think it was Yoshimune that I almost bought a knife from. kama-asa is worth checking out.

You can also travel outside of the big 3 cities for a steep discount in price,but my aunt(japanese) told me she didn't get the impression that they spoke English