Taishoken specializes in tsukemen, a Tokyo style of chilled noodles served with a rich, warm broth on the side for dipping. But in San Francisco, diners can also order an indulgent $35 lobster ramen — if they make it in early; the kitchen will make just 10 bowls a night — topped with half of a roasted lobster, shrimp dumplings and a jammy egg. What goes into the lobster broth, Sakagachi said, is secret. It’s by far the most expensive ramen here; others cost between $16 and $18.

Also new to the menu is a vegan dandan noodle dish, dressed in a soy-sesame sauce and topped with plant-based Impossible meat instead of the typical ground pork.

All the noodles — al dente and slightly nutty from buckwheat — are made fresh on site, and have been a large part of the draw at Taishoken in San Mateo.

The dinner menu includes small plates, from cucumbers topped with dollops of a jalapeno-miso sauce to shira-ae, a mashed tofu salad, smeared on crackers. Cocktails draw on sake and shochu, like the “dirty yuzu” with yuzu pepper and egg white. For dessert, look for new taro mochi doughnuts drizzled in hojicha syrup, and matcha mousse.

Taishoken is one of the Bay Area’s most popular ramen shops and the only one that focuses specifically on tsukemen. In 2019, the Japanese chain opened in downtown San Mateo to much anticipation and long waits. Often lauded as one of the Bay Area’s best ramen cities, San Mateo has been a magnet for both local and international shops, including the first California outpost of a popular brothless ramen chain opening this fall.

Taishoken. Opening Aug. 25. Wednesday-Sunday 5-10 p.m. 665 Valencia St., San Francisco. taishokenusa.com/san-francisco