The Unique Watermelon Culture of Japan: From Square Melons to Luxury Fruits

In most of the world, watermelons are simply a refreshing summer treat—round, juicy, and casually sliced at picnics. But in Japan, watermelon cultivation is an art form, where innovation, precision, and tradition combine to create some of the most extraordinary fruits on Earth. From square and heart-shaped melons to the legendary Densuke black watermelon (which can sell for thousands of dollars), Japan has turned a humble fruit into a luxury commodity and cultural icon.

How did watermelons become such a prestigious product in Japan? And what makes these fruits so unique? The answers lie in Japan’s unparalleled dedication to craftsmanship, aesthetics, and agricultural ingenuity.

Shaped by Design: The World of Square, Heart, and Pyramid Watermelons

One of Japan’s most famous watermelon innovations is the square watermelon, first developed in Zentsuji, Kagawa Prefecture, in the 1980s. These melons are not genetically modified—instead, they are grown in glass or acrylic molds that shape them as they expand.

How Are Square Watermelons Made?

• Farmers place young, growing watermelons into transparent square boxes.
• As the fruit expands, it conforms to the container’s shape.
• The result? A perfectly cubic watermelon—initially created to fit neatly in refrigerators.

But square watermelons are just the beginning. Japanese farmers have also cultivated:

• Heart-shaped watermelons (popular for weddings and romantic gifts)
• Pyramid-shaped watermelons (a novelty item)
• Miniature watermelons (perfect for small households)

These designer fruits are more expensive than regular melons, often costing $100 or more, not because they taste different, but because they represent Japanese ingenuity and luxury.

The Densuke Black Watermelon: Japan’s Most Exclusive Fruit

If square watermelons are fascinating, the Densuke watermelon is legendary. Grown exclusively in Hokkaido, this rare variety has a jet-black rind with almost no stripes, a crisp texture, and an exceptionally sweet flavor.

Why Is the Densuke So Expensive?

Extremely limited production—only a few thousand are harvested each year. Auction prices can reach over $6,000 per melon, making it one of the world’s most expensive fruits. Considered a status symbol, often given as corporate gifts or for special occasions.

The Densuke is so prized that it has its own certification system to prevent counterfeits, ensuring only authentic Hokkaido-grown melons bear the name.

Luxury Fruit Culture: Watermelons as Prestige Gifts

In Japan, high-end fruits are not just food—they are carefully cultivated luxury items, often presented in elegant packaging and given as gifts for business clients, weddings, and VIPs. Department stores like Sembikiya and Takano Fruit Parlor sell premium watermelons for hundreds (or even thousands) of dollars.

This tradition stems from Japan’s gift-giving culture, where presenting perfect, exquisite fruit symbolizes respect and appreciation.

The Square Watermelon Capital: Zentsuji’s Patented Innovation

The town of Zentsuji in Kagawa Prefecture is the birthplace of the square watermelon—and holds a patent on the growing method. What started as a practical solution (making melons easier to store) became a global sensation.

Today, Zentsuji’s square watermelons are mostly ornamental (since they are picked early to maintain shape and aren’t as sweet), but they remain a symbol of Japan’s creative farming techniques.

Other Unique Japanese Watermelons

Beyond designer shapes and luxury varieties, Japan grows several traditional watermelon types:

Striped green watermelons (common in supermarkets)

Seedless varieties (popular for convenience)

Yellow-fleshed watermelons (a sweeter, less common alternative)

Each type reflects Japan’s commitment to quality control and selective breeding, ensuring the best possible taste and texture.

Japan’s Watermelons—Where Tradition Meets Innovation

Japan’s watermelon culture is a perfect example of how the country blends tradition, craftsmanship, and cutting-edge agriculture. Whether it’s a $6,000 Densuke, a geometric square melon, or a perfectly ripe striped watermelon, these fruits are more than just food—they are works of art, status symbols, and testaments to human creativity.

The next time you slice open a watermelon, consider this: in Japan, even the simplest fruits can become masterpieces. Would you pay for a square or heart-shaped watermelon?