Tsai, well-known owner of the Blue Ginger restaurant in Wellesley, prepared “Soy Marinated Alaskan Butterfish” this week in Washington, D.C., at a star-studded State Department lunch honoring Chinese Vice President Xi Jinping, who is expected to be that country’s next leader. It was a take-off on the signature Miso-Sake Alaskan Butterfish Tsai serves at his restaurant.

But as the Globe reported last fall after a five-month investigation into fish mislabeling, the silky fillet on the menu at Blue Ginger at that time was actually sablefish. There are eight other species of seafood that can be called butterfish. But sablefish is not one of them, according to the US Food and Drug Administration’s list of acceptable market names.

And as it turns out, sablefish was served at Tuesday’s luncheon at the State Department, according to Alan Eisner, a spokesman for Tsai.

Read the complete story from The Boston Globe.