A northern-Thai room from three Farmhouse Kitchen alums has opened at 4133 18th St, in the former Thai Chef space. It registered with the City in January as Khamsiri LLC.

Ka Kai Northern Thai is open at 4133 18th St in the Castro, a specialist in the cooking of Thailand's north set into a corner that most recently held Thai Chef. The room registered with the City on Jan. 7, 2026, under the ownership entity Khamsiri LLC, per San Francisco's business registry↗ (external source, opens in a new tab).

The operators are three Thailand-born partners — Kunvadee Doarveang, Tar Watcharin and Pop Navapon — who came up through Farmhouse Kitchen Thai Cuisine, the Bay Area group that has spent a decade making northern-leaning Thai food a going concern here. They took the name from the ka kai, the handmade ceramic bowls used to serve food in Lampang Province, Hoodline reported↗ (external source, opens in a new tab) when the room opened this spring.

The kitchen stays close to the region. The menu runs to larb, sai ua — the herb-packed grilled sausage of the north — and hang lay, the slow pork-belly curry carried down old Burmese trade routes, alongside a six-dish sampler platter built to feed two. There is a northern-style papaya salad cut with black crab paste and a hard hand of lime, and there are cocktails poured into rooster-shaped glasses; the Infatuation, which reviewed the room in April↗ (external source, opens in a new tab), files it as a casual, mid-priced weeknight spot. Ka Kai runs dinner most nights and adds weekend lunch Friday through Sunday.

The bet here is narrow and old: one province's bowls, in a Castro storefront that has cycled through Thai tenants before, run by three people who learned the trade in someone else's kitchen first and are now carrying their own rent. It is the least fashionable way to open a restaurant in San Francisco right now, and often the most durable.