Plenty of Perennials in Japan

I'm just now realizing how many vegetables around me are perennial.

Some are popular elsewhere like #1 and 2

1. 菊芋 (Kikuimo / Sunchokes / Jerusalem Artichokes)
2. Asparagus
3. Watercress
4. 明日葉 (Ashitaba)
5. つるむらさき (Malabar Spinach)
6. 長芋 and 山芋 (Nagaimo and Yamaimo or Chinese and Japanese yams respectively)
7. ハヤトウリ (Chayote / Merlion)

To boot, I actually like all of those, though I haven't tried ashitaba yet.

I am going to let a few of the vines I suspect may be yamaimo vines actually grow this year and see if they produce edible bulbils called むかご (mukago) here. If they do that's yet another plant that I thought was a weed that I was wasting my time cutting.

I've also heard that leaving garlic in the ground essentially turns it into a perennial, so I'm in the trial phase of that.

I need to plant #1, 2, 4, and 5.

Combine those with a variety of fruit trees and that's a pretty solid low-maintenance perennial food garden.

People talk about perennial kale, spinach, and walking onions too... but I don't hear many people planting those around here, so we'll get to them in later experiments...

Chayote vines are very productive. I got over 50 squashes from these last year.

I think you're just a bit warmer than me in terms of climate, so some of those may be more difficult for me to grow.  I have some Angelica archangelica (rather than Angelica keiskei), which has flowered spectacularly for me this year, so hopefully plenty of seeds.
I've been trying more sansai, mountain vegetables see My SkyeEnt blog for a intro.  Some of these may cope better with my cool summer.
Japanese ginger (Zingiber mioga), seems to be struggling to get going.  I suspect it needs it a bit warmer because I know it can grow thuggishly further south in UK, so I may transplant some into sunnier spot. Toona sinensis is still alive, although not growing enough to harvest more than a tiny nibble. Fiddlehead fern, Matteuccia struthiopteris I have in a couple of places, still disappointingly small in second year. Hosta are doing fine, as are daylillies.  Aralia elata are establishing well, so I may get to try them next year...The akebia has yet to flower.  Most are in the polytunnel, but I planted a couple of seedlings outside, and they survived what for us was quite a cold winter spell in March.  I'm lettin Diascora japonica go wild in thd polytunnel.  I'm thinking of harvesting the bulbils annually, but the roots every 4 years, according to the crop rotation I have where I move the tomatoes (and therefore Yacon).  Many of the root crops need more than one year to reach a decent size, so this may work.....
Bracken fern (waruba) is a pestilential weed here, but given it's reputation for toxicity I have not tried it yet.
Oh and Wasabi seems to like it here, although we don't like it much - not into hot food like that.