Several trees grow on our small plot of land as well here in the countryside of Kyushu, including kabosu, sudachi, daidai, and yuzu. Varieties like these join an array of bitter citrus that also includes shikuwasa and busshukan. All are prized for the vital role that their aromatic zests and sour juices play in flavouring the country’s cuisine. But yuzu stands above the rest, celebrated for centuries in Japan’s culinary traditions and more recently beloved around the world. People draw on a myriad of references when trying to describe its intoxicating fragrance, often referring to it as mandarin-esque crossed with either grapefruit, lemon, or lime. But yuzu is distinctly yuzu, its finest attribute a thin outer skin flush with oily perfume.

In the refined and subtle culinary tradition of cha-kaiseki, the principal meal of the tea ceremony, wanmori, a dish served in a covered lacquer bowl, is considered the pinnacle. Guests lift the bowl and cradle it in one hand before gently removing the lid. Inside, seasonal ingredients rest in a pool of clear broth. A waft of fragrant steam rises. Often, in winter, a sliver of bright yellow yuzu rind crowns the arrangement. You gently clasp it between the tips of your chopsticks and hold it at the rim of the bowl, allowing the broth to wash over it on the way to your lips. Its perfume adds a spirited piquancy to a flavour so light, clear, and savoury.

Much is written about the artistry and aesthetics of Japanese cuisine for good reason. It is understood in Japan, perhaps better than anywhere else, that we consume first and foremost with our eyes. The impact of colour and arrangement most immediately captures our attention and whets our appetites. But scent is a powerful and invisible element that speaks to us on another dimension. Fragrance has the capacity to invoke memory and emotion and a whiff of yuzu instantly locates us in this very moment when winter is settling in. Yuzu is one of many prized ingredients used as a suikuchi, an aromatic garnish in Japanese food. In this role, it is used with noticeable restraint; and yet, it is fundamental to the experience of the dish.

Restraint and essence are exactingly expressed in Japan’s most refined culinary traditions, which originated in Kyoto. But here in Kyushu, where temperatures and temperaments run hotter and flavours run bolder, yuzu shines in a radically different form. Yuzukosho, one of Japan’s staple condiments, is a local specialty. This potent paste is made by blending the zest and juice of yuzu with fresh togarashi (chilli peppers) and fermenting with salt. Often made with immature green yuzu and green chillies, it packs a spicy, citrus punch. But I was first introduced to a stunning orange version flecked with red chilli flakes and made with the yellow zest of ripe yuzu, which has a more floral fragrance and also a natural sweetness that balances the piquancy. Smitten, I immediately wanted to know how to prepare it myself and so asked my mother-in-law about its origins, only to be told that the local woman who makes it guards the recipe so fiercely that even her own daughter doesn’t know the details. I buy a jar of it each year and use it with the utmost delight as a condiment for grilled fish or in place of wasabi to accompany sashimi. But its applications are endless and a dollop of green or orange yuzukosho adds a burst of life to soups, noodles, and so much more.

A yuzu tree full of ripe fruit is a thing of beauty. The memory of an early, misty, harvest morning on a visit to a yuzu farm in Kagoshima stays with me always. The rays of the winter sun struck a thousand dewy droplets strung along the threads of a perfectly spun spider’s web. It sparkled in the morning light. I watched as an 80-year-old yuzu farmer donned thick leather gloves to protect his hands and arms from the needle-like thorns that line the tree’s branches. He climbed a ladder to cut a few fruit for me to take home, a gift that felt akin to receiving orbs of gold. It is said that a yuzu tree grown from seed can take up to 18 years to bear fruit. But if there is one thing Japan’s cuisine and its practitioners embody, it is patience in the pursuit of perfection. The fruit on my tree aren’t as admirable as the ones on that farm, but they are no less beloved.

It is time to harvest a dozen or so for New Year’s yubeshi, a kind of traditional Japanese confection. Ripe yuzu are hollowed out; packed with a rice flour, miso (fermented soybean paste), and nut filling; steamed; and set to cure outside on sunny days for several weeks. The flavours mature and meld as the fruits dry to leather-hard just in time to slice and serve as part of the ceremonial first meal of a new year.