<p>Following up on the original question... Concise Products in Japan seems to still be producing circular slide rules <a href="https://www.sliderule.tokyo/products/detail.php?product_id=7" target="_blank" rel="nofollow noopener noreferrer" translate="no"><span class="invisible">https://www.</span><span class="ellipsis">sliderule.tokyo/products/detai</span><span class="invisible">l.php?product_id=7</span></a></p>