I believe Concise[1] in Japan still make circular slide rules. I bought a No. 300 and No. 270N from them a few years ago. [1] https://www.sliderule.tokyo/produ

I believe Concise[1] in Japan still make circular slide rules. I bought a No. 300 and No. 270N from them a few years ago. [1] https://www.sliderule.tokyo/products/list.php https://www.sliderule.tokyo/products/list.php