About Oka no Ue no Koji Kobo

Hello travelers! I’m Aikero, a writer for Sarukuma.
I’ve been curious about this spot for ages, and I finally made the trip (#^.^#)

Today I’m introducing a delightful little gem in Mitsugi-machi, Kita-ku, Kumamoto City:
Oka no Ue no Koji Kobo (The Koji Workshop on the Hill).
This unique shop is run by Hashimoto Shoyu, a soy sauce brewery founded back in 1919 (Taisho 8). They specialize in koji donuts and koji lattes made with traditional sweet sake (amazake).
What began as pop-ups at events and festivals has now become a permanent fixture at the Hashimoto Shoyu shop.
Located near Food Pal Kumamoto but tucked away in a quiet spot, this is a true hidden gem that only those in the know have discovered!

Across from the Food Exchange Hall parking lot, you’ll spot the Hashimoto Shoyu sign.
I’d seen it before, sure—but I never knew they served sweets here! Then I noticed the donut flag waving in the breeze Σ(･ω･ﾉ)ﾉ!
Following the sign, you’ll turn and head down the road, wondering if you’re going the right way…
Keep going, and the entrance will appear right where it should be (^^)/
Bonus: the parking lot is very spacious!
The exterior looks very much like a working factory, which can be a bit intimidating—but trust the donut flag and head on in!
Get closer, and you’ll see you’re in the right place!
The variety of donuts and drinks is even more impressive than expected!
When you open the first door, you’ll see two more doors on either side.
Go through the door on the LEFT (^^)
Inside is a combination office and shop space.
As you’d expect from a soy sauce brewery, all kinds of beautiful soy sauces line the shelves!
Toward the back, you’ll find the amazake (sweet sake) and miso section.
And here’s the main attraction—the koji donuts (●＾o＾●)
They’re a bit larger than your typical donut, though it might be hard to tell from photos!
Fluffy ones, crunchy ones, eye-catching toppings galore—it’s exciting just looking at them ♫

The story behind these donuts is sweet too. While selling koji lattes at events, the team kept hearing customers ask, “Don’t you have any sweets?”
Combined with the fact that the president of Hashimoto Shoyu loves donuts, the factory manager (a former pastry chef) and staff started experimenting with what they thought would taste great—and the koji-infused donut was born!
Koji donuts can also be reserved by phone (^^)/

〈Top Row〉
・Plain Ring 300 yen
・Sugar Donut 300 yen
・Kinako (Soybean Flour) Donut 300 yen
・Chocolate Ring 330 yen
・Caramel Nut 380 yen
・Choco Crunch 380 yen

〈Bottom Row〉
・Gottsu Chocolate 330 yen
・Gottsu Honey Lemon 350 yen
〈Top Row〉
・Strawberry Paradise 380 yen
・Matcha Ring 380 yen

〈Bottom Row〉
・Gottsu Matcha 330 yen
・Gottsu Strawberry 330 yen
The koji latte was created to share the deliciousness of the amazake that has been brewed here for over 90 years.
It’s a smooth, strained amazake combined with milk, matcha, and other flavors.
No sugar is added—just the natural sweetness of rice koji shines through.
〈Koji Latte〉
・Cocoa Koji Milk 550 yen
・Matcha Koji Latte 450 yen
・Hojicha Koji Latte 450 yen
・Black Sesame Koji Latte 500 yen

〈Amazake〉
・Amazake 400 yen
・Milk Amazake 450 yen
・Vanilla Milk Amazake 450 yen

〈Coffee〉
・Americano 400 yen
・Cafe Latte 450 yen

All drinks can be ordered hot or iced.
・Rich Premium Amazake SEIRAN from 370 yen

Wondering why a soy sauce brewery makes amazake?
Soy sauce, miso, and amazake are all fermented foods—and they all share one essential ingredient: koji.

Hashimoto Shoyu’s Rich Premium Amazake SEIRAN carries on the recipe originally created by the founder’s wife.
It’s sweeter than store-bought amazake, and you can enjoy it straight, mixed with milk, drizzled over yogurt, and so much more ♫
While we’re here, let’s take a look at the soy sauces too!

・Tamago Gohan Senyo Konbu Shoyu (Egg-on-Rice Kombu Soy Sauce) 420 yen
Soy sauce specifically for tamago kake gohan (egg on rice) isn’t unusual today.
But I had no idea Hashimoto Shoyu was the original creator!
They wanted children to eat breakfast, so they reached out to fellow brewery members, and various “egg-on-rice soy sauces” were released across the region.
・Amakuchi Sashimi (Sweet Sashimi Soy Sauce) 420 yen
This sweet, syrupy soy sauce is a Kyushu specialty.
It makes a wonderful souvenir for friends from outside the prefecture ♫
They also have sweet-and-spicy sauce, yakiniku sauce, mentsuyu (noodle dipping sauce), and ponzu!
Salt is also available—pretty much any seasoning you might need is here (●＾o＾●)
And the donuts you buy can be enjoyed at the outdoor eat-in space ♫

Recommended Menu Items at Oka no Ue no Koji Kobo

I picked up a Black Sesame Koji Latte and three different koji donuts ♪
Koji donuts and koji lattes—doesn’t that just sound healthy and wonderful?♡
You could even take them to nearby Food Pal Kumamoto, the lawn area at the Food Exchange Hall, or Izumi Mitsugi Green Park (Food Pal Kumamoto Park) for a lovely picnic ♫
The black sesame gradient is so pretty (*’ω’*)
When you think of amazake, you probably picture a thick texture with grains of rice, right?
But because the koji latte is strained, it’s smooth and silky—with a gentle sweetness that’s still unmistakably present!
If no one told you, you might not even guess it was amazake!
Receiving little messages like this one always brings a smile (#^.^#)

Because there’s no sugar added, it leaves a clean finish—perfect for hot days, and I’d definitely order it again!
The black sesame flavor was absolutely fantastic ♫

Amazake is so nutritious it’s often called “a drinkable IV drip” in Japan.
Even if you’re not usually a fan of amazake, I’d really encourage you to give the koji latte a try.
And of course, amazake lovers will adore it too!
The koji donuts are slightly oversized.
They’re roughly a bit bigger than the palm of an 8-year-old (^_^;) (admittedly a vague reference, haha)
I ate them the next day after buying, and they were still wonderfully fluffy ♡The koji flavor isn’t strong, so kids gobbled them right up too ♫
The Gottsu Honey Lemon comes topped with lemon peel and icing sugar.
It has a delightful crunchy texture with a delicate, gentle sweetness.

Both styles were delicious, but personally I’m Team Gottsu (*’ω’*)
The kids preferred the fluffy ones ♫
Koji donuts and koji lattes, lovingly crafted by a soy sauce brewery.
It’s tucked away in an unexpected spot—a true hidden gem with sweets you won’t find anywhere else. Definitely worth a visit ♫

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Frequently Asked Questions

※Information accurate at the time of reporting. Prices and hours may change. Please confirm before visiting.