The first thing you notice about Aozora Blue, chef Hirofumi Matsui’s Michelin guide-listed udon noodle restaurant in Hiranomachi, Osaka, is that it doesn’t really feel like an udon restaurant. It’s DNA is much closer to that of a soba restaurant.

That’s both deliberate and understandable. Prior to opening Aozora Blue at the end of 2014, Matsui had spent the previous 15 years making soba.

As Matsui, 44, recounts, the first time he ate at Dosanjin, a soba restaurant in central Osaka where noodles are made by hand, he was “shocked at how good the soba was.”

So good in fact, that Matsui stayed at Dosanjin for the next 15 years learning the craft of making handmade soba, from grinding the flour in a millstone to the delicate process of rolling out the dough and stretching and slapping it into sheets of glistening soba dough.

As Matsui approached his 40th birthday, however, he was ready for a change. He had been mulling over whether to go out on his own and open a restaurant, after all he had banked a considerable amount of his life working in a kitchen, but at the same time he wanted to forge a different path.

“If I was going to do something, I wanted it to be challenging so that it would enrich my life,” Matsui says.

So he stepped away from soba, opting instead to make udon, which he had developed a taste for at a young age.

The result, Aozora Blue, is an udon restaurant where both the noodles and the restaurant’s interior are a nod to Matsui’s soba schooling.

For starters, the process of making the udon is taken straight from the soba playbook; Matsui uses a millstone to grind his noodle flour. He also has specific demands when it comes to his flour suppliers. He wanted the grain intact; usually it’s ground down in the milling process before it reaches the kitchen at udon restaurants.

But, as Matsui said, “so much is lost in that process, especially the scent and the feel.”

His method is a time-consuming one — one batch of flour takes up to two days to make, alternating between milling and sifting until it’s finally ready to be made into dough, rolled out and cut up. But, Matsui has faith in the process, and the outcome.

At Aozora Blue you can choose from either the house speciality jikaseibun arabiki (udon made from house-made coarsely ground flour), which, were it not for the noodles girth, look closer to soba noodles. They don’t taste like conventional udon noodles either, rather the noodles hone closer to the flavor of soba, but with more of an al dente bite to them.

There’s also the so-called “blend noodle” (made from a mixture of various wheat flours) that is much closer in appearance to standard white udon.

Matsui said he wasn’t interested in developing different noodles just for the sake of it.

“Only making customers go, ‘Oh this is unique,’ is not enough,'” he says. “There has to be a moment when the customer goes, ‘It’s unique, and tastes good — I love it.'”

House-made: The noodles at Aozora Blue have a soba-like appearance, unsurprising given chef Hirofumi Mitsui’s 15 years of experience at soba restaurant Dosanjin. | J.J. O’DONOGHUE

Matsui didn’t completely abandon the udon restaurant way of doing things: the compact menu features a strong showing of tempura dishes, complemented with petite rolled sushi sets.

As with any worthwhile soba master Matsui has a keen appreciation for nihonshu (sake), too, and likes to pull in different brews from across the country.

As for the restaurant, it’s modern, minimalist and comforting. Matsui thinks that modern udon restaurants share an identity that is closer with ramen restaurants.

“But I went for soba style,” Matsui says. “I wanted it to be a modern space, but one that reflects udon’s wa (Japanese) heritage. I really cared about the balance of these two forces when I created this place.”

From time to time, Matsui is also happy to give the restaurant a whole new temporary identity. At one pop-up event he hosted, the restaurant was turned into a bar. Takashi Watanabe, a musician and composer who has worked on a number of films including “Fune o Amu” stepped in as bartender for the night while his music played over the speakers.

Nights like this, though, will probably be put on hold for a while. Matsui is now working on the goal he set himself when he opened Aozora Blue: Within 10 years he wanted to have three udon restaurants up and running. Now, five years in, number two is on course for this fall, when Mitsui will open a store in the Daimaru department store in Shinsaibashi, giving Osakans another chance to enjoy great udon in a soba-style restaurant.

English menu; some English spoken

Aozora Blue Osaka Restaurant Page Aozora Blue Osaka Name (J) 青空blue Lunch price range ¥3,000 or more Cuisine Japanese Keywords udon Number of seats 33 Smoking No smoking Reservations Not accepted Area Osaka Address 4-5-8 Hiranomachi, Chuo-ku, Osaka Address (J) 大阪府大阪市中央区平野町4-5-8 Telephone 06-4708-8812 06-4708-8812 Website http://www.aozora.blue/ Hours 11:30 a.m.-2:30 p.m., dinner 5:30 p.m.-10:30 p.m. (Sat. till 9:30 p.m.) Payment information Cash English spoken? Yes Map

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KEYWORDS Osaka, soba, Udon