Rare Ricoh Slide Rule No. 505 / Pocket Type [With Instruction Manual & Storage Case]

Ricoh Slide Rule No. 505 / Pocket Type
[Includes Instruction Manual & Storage Case]

This is an analog calculating tool called a slide rule (keisanjaku) that was widely used during the Showa era.

Product Details
○ Manufacturer/Model: RICOH (formerly Riken Optical Industries, San-ai Keiki, etc.) No. 505, a 5-inch, pocket-sized, single-sided model.
○ Features: By sliding the sliding scale (zubeshaku) in the center, which is engraved with scales, left and right to align numerical positions, advanced calculations such as multiplication, division, square roots, and logarithms can be performed quickly.
○ Special Notes: The organization name Kyushu High Pressure Gas Safety Association is printed on the lower part of the back, suggesting it was a special novelty item distributed as a commemorative gift for seminar participants or members, or possibly a company-issued item at the time.
It was a must-have item for engineers, researchers, and students until the advent and popularization of electronic scientific calculators in the late 1970s. It is no longer produced and appears to be traded among collectors as a Showa retro vintage item.

There are some minor stains and fading due to long-term home storage. It is considered to be in relatively good condition for its age, but we ask for your consideration if you understand that it is a home-stored item.
All items shown in photo 1 are included.