You might be wondering who looked at a spiky, deep-sea echinoderm and thought, “Ah, yes, let’s put that in a milk bottle.”

It turns out, Yamada Town in Iwate is actually considered the birthplace of this ingenious packing method! Back in the post-war era, local women would travel to nearby cities to sell their fresh catch. Initially, they transported the delicate sea urchin in long plastic bags, but the precious cargo would often get squished into a mushy (albeit tasty) paste.

By the late 1960s, someone had a brilliant idea: repurpose small glass bottles. The rigid glass protected the incredibly fragile uni, and immersing them in sterilized seawater kept them plump, fresh, and visually stunning. Today, the sight of those fluffy, pale-orange pillows floating in a clear bottle isn’t just practical; it’s a nostalgic, Instagram-worthy symbol of a Sanriku summer.

Most commercially available sea urchin uses a food additive called alum to help it keep its shape during transport. Unfortunately, alum is exactly what can give uni that slightly weird, bitter metallic aftertaste that can turn people off.

Sugawara Shoten’s milk bottle uni throws the alum out the window. Inside the bottle, there are exactly two ingredients:
1. Premium Kita-Murasaki Sea Urchin (hand-harvested in Iwate)
2. Sterilized Yamada Bay Seawater

That’s it. It’s as close as you can get to sitting on a dock and cracking one open yourself. The result is a pure, melt-in-your-mouth sweetness that tastes exactly like a fresh ocean breeze.

Now that you have your glorious bottle of ocean gold, what do you do with it?

Iwate ranks as the #2 producer of sea urchin in all of Japan, and holds the crown for the highest catch volume on Japan’s main island of Honshu. The nutrient-rich waters of the Sanriku Coast provide the perfect habitat.

But you can’t just go out and grab these urchins whenever you feel like it. To protect the ocean’s resources, Iwate has incredibly strict fishing rules during uni season—from early May to early August.

Local fishermen have designated “mouth-opening” (kuchi-ake) days—the only specific days they are legally allowed to harvest. On top of that, they can only keep urchins larger than 5 centimeters, and if the wind is howling or the waves are too high, fishing is canceled entirely. Because of this, every single bottle is a precious, weather-dependent summer miracle, meticulously sorted and packed by hand with chopsticks.

So, are you ready for a taste of the Sanriku summer? Have a look at Sugawara Shoten Online Shop or drop by during your coastal road trip!