HEMMI Slide Rule - Shōwa Retro This is a case for a bamboo slide rule made by Hemmi Bamboo Slide Rule Mfg. Co., Ltd. The following information is printed on the case: Manufacturer: Hemmi Bamboo Slide Rule Mfg. Co., Ltd. Material: Bamboo (BAMBOO) Brand Name: SUN Product Type: Slide Rule (SLIDE RULE) This case is for protecting and storing a slide rule, an analog calculation tool that was once widely used.