When you visit Ōmi, you’re sure to hear at some point that Mt. Ibuki, the region’s highest mountain, is where soba buckwheat originated in Japan. This may not actually be true as we’ll learn shortly, but Ibukisan and its environs are certainly ideal for growing and eating this unassuming but delicious grain.

Due to its exposure to the cold winds off the Japan Sea, Mt. Ibuki has the highest recorded snowfall in Japan. When the snow melts, it produces prodigious quantities of pure water which flows into Lake Biwa. Ibukisan is a limestone mountain, and the combination of good water, lime-rich, volcanic soil, and a significant difference in temperature between day and night, is optimal for cultivating soba.

The seeds of Ibuki soba are similar to other types in shape, but they’re smaller. However, the growing plant is characterized by a deep green colour. The flour produced from the seeds has a strong aroma, and noodles made from it are particularly rich, sweet and firm of texture. Fortunately, the ideal conditions for growing buckwheat happen to favour other vegetables that go well with soba noodles, such as daikon and mugwort.

Daikon is a large white radish grown all over Japan, but Ibuki daikon is a distinct variety unique to this part of Ōmi, a traditional vegetable that has been cultivated since ancient times at the foot of Mt. Ibuki. The leaves and neck are purplish red, the root itself is thick, round and firm, and the tip is long like a mouse’s tail, so it was known locally as “mouse radish”. Otherwise, there’s nothing mousey about it.

All daikon has the interesting characteristic of becoming hot to the taste when grated, but Ibuki daikon has twice the pungency of the conventional white radish, so when it’s grated and served with soba noodles, there’s no need for the spicy wasabi that typically accompanies soba in other regions. When the daikon is chopped for salads or pickled however, it has a gentle aroma with a beguiling crunchiness.

The strongly aromatic mugwort of the Ibuki region is typically made into tempura which is served as a side dish to buckwheat noodles.

So why is the origin of soba in Japan associated with Ōmi? Buckwheat is thought to have originated in Yunnan Province in China. In Japan, buckwheat pollen has been found at numerous sites from the Jōmon period when buckwheat cultivation started. Genetic analysis has shown that its cultivation spread from northern China to Japan via the Korean Peninsula. Based on the number and distribution of the archaeological sites, it appears that buckwheat cultivation was widely established in the Nara and Heian periods and became most widespread in the Middle Ages.

However, the prominent and highly visible location of soba cultivation in Ōmi on the flanks of Mt. Ibuki is what led to the region’s reputation as the starting point of soba. Mt. Ibuki, located on the border between Shiga and Gifu prefectures, is known as a base for mountain worship and as a sacred place for mountain asceticism. Cultivation of Ibuki soba began in the late Heian and Kamakura period at Taihei-ji Temple on the side of Mt. Ibuki. It started as a means for the monks and ascetics to secure a source of food. The area around Taihei-ji is characterised by limestone soils and steep slopes and so it isn’t suited to rice paddies. So the monks began to grow buckwheat, which happens to thrive in these conditions.

Contemporary records state that a sea of white soba flowers could be seen from Nagahama, and even as far away as Takashima on the opposite shore of Lake Biwa. Mt. Ibuki is the point where the cultures of eastern and western Japan intersect, and it’s a place where land and water traffic routes met. It’s thought that this landscape of highly visible buckwheat fields became widely known to local residents and visitors to the area, so that gradually the foothills of Mt. Ibuki came to be called the origin of soba cultivation in Japan.

A picture of Mt. Ibuki in the family documents of the Ii clan shows a soba field on the west side of Mt. Ibuki, above Taihei-ji Temple. According to historical documents, the Hikone Domain made a gift of Ibuki soba and hot daikon to the Edo Shogunate, singing its praises. Thereafter, Ibuki soba became a popular item that was used as a gift to feudal lords and retainers and was served as a special treat for visitors to Taihei-ji Temple.

Today you can enjoy the rustic and nutritious taste of Ibuki soba at many places in Ōmi. But where better to experience it than at the foot of Mt. Ibuki itself, in a traditional building of the region? Located in a hamlet in Maibara, right under the mountain, is a restaurant called Kyūjirō. You’ll notice that under its brightly coloured eaves, its heraldic mark is unusually, a “mouse daikon”. At Kyūjirō, you can taste for yourself the delicious soba, daikon, and other supremely tasty and nutritious foodstuffs that sustained the mountain ascetics of Ibuki in the olden days. And you can even buy the ingredients there to take away and make at your leisure.