Japan's Udon Types — From Sanuki to Inaniwa and Why the Region Defines the Noodle

Udon is Japan's thick wheat flour noodle — but the category contains more variation than any single bowl suggests. The thickness can range from 3mm (Inaniwa) to 8mm or more (Sanuki). The texture can be chewy-elastic, soft-silky, or springy. The cross-section can be round, square, or flat. Each regional style reflects a different optimization for texture, local water quality, and tradition.

Sanuki Udon (讃岐うどん) — Kagawa Prefecture

The most famous and most imitated style. Sanuki (the old name for Kagawa Prefecture on Shikoku island) produces a noodle characterized by:

• Thickness: Medium-thick, roughly 3.5-4.5mm
• Cross-section: Square edges (distinctive)
• Texture: The defining characteristic — koshi (コシ). An extreme chewiness and elasticity. The noodle resists the bite, snaps back, and has a structural integrity that softer udon lacks.

Why Sanuki produces this texture: The specific wheat varieties grown in the Sanuki Plain combined with the region's soft water (low mineral content, which affects gluten development) produce a noodle dough that, when properly worked, develops exceptional gluten structure.

How to eat: In Kagawa, udon is eaten as the cheapest, most casual possible food. A bowl of basic kake udon (plain broth, nothing on top) costs ¥150-200. Self-service shops where you carry your bowl and add your own toppings dominate. You eat standing. You don't linger.

Inaniwa Udon (稲庭うどん) — Akita Prefecture

The opposite of Sanuki. Where Sanuki is thick and chewy, Inaniwa is thin (2-3mm), flat, silky, and smooth.

Production method: Inaniwa is hand-stretched — made by repeatedly twisting and stretching dough around two wooden dowels until it becomes extremely thin. This process is more labor-intensive than machine rolling and produces a different noodle structure: less gluten network per cross-section, resulting in the silky texture.

History: Considered one of Japan's three great noodles (along with Sanuki udon and Nagatoro somen). A feudal gift to the shogunate in Edo period.

Served: Usually cold (zaru style, with dipping broth) rather than hot, because the delicate texture is better showcased cold. The silky surface catches the tsuyu differently from thick noodles.

Kishimen (きしめん) — Nagoya

Flat, wide, and thin. Kishimen is cut into wide flat ribbons (5-7mm wide, 1-2mm thick) rather than round or square cross-sections. The large surface area makes it cook quickly and creates a soft, almost pasta-like texture — less chew than Sanuki, but distinct from Inaniwa's silkiness.

Nagoya serving style: In strong dashi (katsuobushi-forward), with flat slices of kamaboko fish cake, spinach, and bonito flakes on top. The broth tends to be darker than Kyoto or Tokyo styles.

Goto Udon (五島うどん) — Goto Islands, Nagasaki

Made with a small amount of camellia oil incorporated into the dough. The oil coats the gluten strands, producing a distinctly springy, elastic texture different from either Sanuki or Inaniwa.

Serving style: Jigoku daki (地獄炊き — "hell cooking") — the udon is cooked in boiling water at the table and dipped in raw egg and soy sauce. Very old-fashioned preparation.

Tokyo vs Osaka Broth

The noodle styles involve regional variation, but so does the broth:

• Tokyo (Kanto) style: Darker broth, more soy-forward, higher salt content. Uses koikuchi soy.
• Osaka (Kansai) style: Lighter-colored broth (uses usukuchi light-colored soy), more subtle, dashi-forward. The Osaka claim is that light broth showcases the noodle rather than overwhelming it.

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Udon's regional diversity reflects how a single simple ingredient (wheat flour, water, salt) can produce radically different eating experiences depending on technique, wheat variety, water mineral content, and tradition. The noodle itself is the product — not the toppings. The regional udon shops of Japan treat their noodles with the same specificity that a winery treats their grape variety.