Hi everyone. Considering a three week trip to Japan and am interested in off-the-beaten path spots that are big on culture. I had originally wanted to go to Hanoi and Hoi An in Vietnam to give you a taste of the flavor I’m after. I know they are very different places but curious if anyone has suggestions. Thank you

When is your trip? What month(s)? Why Japan? What are your interests for visiting there?

Most of the paths in Japan are beaten to some extent - there are a lot of Japanese tourists in addition to foreigners. So there are a couple of "grades" of well-beaten. First by most foreign tourists and by Japanese, then fewer foreign tourists but still popular with Japanese, then no foreigners. It is that last group, the places where you look around and you are the only foreigner are what I think of as off the beaten path. The well beaten paths are that way for good reason. You could think of the beaten-ness of a path as holding world-class, national, regional, or local interest. If you don't get on any of the well-beaten path then you could miss a lot.

I would not consider Hanoi or Hoi An to be off the beaten path. Maybe you are thinking that Vietnam is off the beaten path, I suppose it is, compared to Japan. Or Hanoi compared to Tokyo or Bangkok.

Having taken my first trip to Japan two months ago, I was in a similar situation. While I don't like crowds, I followed the advice of mrwunrfl and other Fodorites to study the japan-guide web site to figure out what areas appealed to me. I knew i wanted to focus on gardens and nature, so that helped direct my planning. Of course, I couldn't visit Japan without visiting some temples so I used maps and advice to plan an itinerary. Since I've travelled a lot, I do visit some of the sites on the "Top 10" lists wherever I go - after all, I figure that there's a reason they are on that list ! (Even then, I focus on places that appeal to me - stately homes, museums, architectural sites, gardens, etc - I run the other direction from theme parks or shopping malls!) What I'm saying is that mrwunrfl articulated the types of attractions very well and that as a first time visitor to Japan, if you only search out "off the beaten" spots, you will miss some wonders and a unique perspective. You know your travel style and should build that into your itinerary; for example, I went to a number of the "Top 25" temples and gardens in Kyoto but knew there would be tour groups so planned to let them get ahead of me (or vice versa) so I could enjoy in relative peace & quiet. After two days of these Top sites, I revised my remaining itinerary to focus on temples & sites that were geographically out of the main area; my thinking was that tour buses generally visit sites that are near each other and I didn't think they'd take the time to go off the tourist path. I enjoyed these other sites immensely - these were sites where i was one of the only foreigners. So, my recommendation is to research and craft an itinerary that covers your interests and gives you flexibility to change on the go. With hindsight, i'm glad I went to the Top 10 places that I did visit and I was always able to find my own space there; but I'm equally pleased that I adjusted my plans mid-stream to visit amazing places that were uncrowded. (You can find my trip report by clicking on my name if you're interested).

If by "off the beaten path" you mean "not overrun with tourists" Hoi An is not a place you should ever have considered.

In Japan you will encounter fewer foreign tourists on the north coast of Honshu (maybe Kanazawa but more likely Matsue) and on the other islands (Nagasaki rather than Hiroshima, for instance).

I love going to the hidden gems of Japan. They are getting fewer and fewer though. I just went to Kyoto and Nara a couple weeks ago, and it is now just one giant Chinatown. Even saw a storefront barker calling out in Chinese to visit their store.
You will find far fewer in the northern part of Japan, in the Tohoku Region - but I saw many tourists there too. If you want a nice and relaxing traditional experience, take the Geibikei boat cruise in Iwate. Beautiful, and unforgettable.
For some traditional places all over without the crowds, try visiting some of Japan's traditional gardens. Many of the tourist mobs skip them, yet they are marvelous.

Vietnam has absolutely NOTHING to do with Vietnam, apart from the mountainous terrain in both countries : Japan is ultra-modern + eons-old culture, Vietnam is infinitely less developed, with less population and, above all, 53 Minorities which have kept their centuries-old customs, each with different costumes, house architecture, dances etc., etc.. Finally, everything is Vietnam is as cheap as it is atrociously expensive in Japan (25-30$ for a room in an excellent 3-star hotel compared with 60 and over for ex.)

Vietnam has absolutely NOTHING to do with Vietnam...

You might want to rephrase that.

And not everything in Japan is "atrociously expensive" at all. There are lots of cheap and clean hotel accommodations, even as low as US $30, in Tokyo and other cities, not to mention lots of air and rail passes plus low cost carriers - I can fly across Japan for US $50. And food can be cheap or expensive, depending on what you want. To say Vietnam is inexpensive is a fair statement, but many things in Japan compared to other developed nations (probably yours) are not atrocious at all - some are in fact dirt cheap - for those that know where the good deals are.

What Adastra said. Of course you can spend obscene amounts of money in Japan, especially if you patronize a lot of ryokans and eat a lot of Kobe beef, but you certainly don't have to.Equally, you can travel quite cheaply. Probably not as cheaply as you could in Vietnam, if you chose to, but no more expensively than western Europe.My second (solo) trip to Japan, in fall 2016 lasted 38 days and cost an average of 170/USD a night including all meals and transport in country, and I could easily have spent less if I had wanted less comfort.

I don't want cheap. I want inexpensive or, even better, a good deal, a bargain. I want good value. A JR Pass, for example, is not cheap because there is nothing cheap about JR trains, but it can be a great value.