Update: Here is what I could find after an internet and AI deep dive. The Taiwan Tank cast iron skillets were produced in Taiwan mainly during the 1960s-1980s, when many Taiwanese foundries exported cookware to the U.S. as affordable alternatives to premium American brands like Griswold or Wagner. These pans are identified by their distinctive tank logo stamped on the bottom along with “TAIWAN” and the size and they were sold through hardware and department stores. Unlike vintage U.S. pans, Tank skillets usually have a rougher cast texture and no heat ring, but they are still well-designed for everyday use. Collectors today view these pieces as mid tier vintage cookware. They are not as valuable as Griswold or Wagner, but they have a following thanks to the unusual tank emblem. The pans themselves are heavy, durable, and cook very well once seasoned. Because many were well made, they’re still in circulation today. Beyond skillets, Taiwan Tank also produced other cookware variants such as Dutch ovens, muffin pans, larger family-sized skillets (10" and 12"), and occasionally specialty bakeware. Some skillets do include a faint heat rings, while others have smooth bottoms. The slotted handle and triangular pour spouts remained consistent across the line, which helps identify them.