Here is a comparison I made back in 2015:
The Jamestown Lounge and Kosuga chairs are very similar, with the following differences that I can tell so far:1. Jamestown has a contoured fiberglass base for the cushioned seat, while Kosuga is flat plywood.2. Seat framing is different.3. Leg bases are different.4. Jamestown has oak framing with a walnut stain. Kosuga looks to be walnut stain on a different hardwood.I also found a photo online of a similar all-oak chair, including contoured seat and backrest. I assume this is a variation of my Jamestown chair.
In hindsight the Jamestown chair could have been stained elm. I was not so good at wood ID back then (still not so good), so I interpreted elm as strong-grained oak more than once. Here are photos of the Jamestown chair that I had.
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