Riken Corporation

Company Profile




Sanbancho Tokyu Bldg., 3F, 8-1 Sanbancho, Chiyoda-ku, Tokyo, 102-8202 Japan

Business Overview

-A major supplier of piston rings in Japan.

-Sales at the automotive and industrial-machinery business were JPY 72.9 billion in the fiscal year that ended in March 2023, accounting for 84% of total sales.

-Riken Corporation (Riken) and Nippon Piston Ring Co., Ltd. (NPR) announced that they have established a wholly owning parent company of both companies, NPR-RIKEN Corporation, through a joint share transfer.


-Listed on the first section of the Tokyo Stock Exchange. (As of Mar. 31, 2023)
Name or Company Name Investment Ratio (%)
The Master Trust Bank of Japan, Ltd. (Trust Account) 9.78
Mizuho Bank Ltd. 4.84
Nippon Life Insurance Company 4.27
Daishi Hokuetsu Bank, Ltd. 3.19
Custody Bank of Japan, Ltd. (Trust Account) 2.75
Sumitomo Mitsui Trust Bank, Limited. 2.61
MUFG Bank, Ltd. 2.54
Riken Kashiwazaki Stock Ownership Plan 2.40
Sompo Japan Insurance, Inc. 1.89
Proterial, Ltd. 1.76
Total 36.04


Piston rings

Engine parts
-Valves seats
-Valve lifters
-Valve spring retainers
-Expansion chambers
-Rocker arms

Transmission parts
-Seal rings
-Differential cases
-Pinion shafts

Drive and chassis parts
-Steering knuckles
-Damper forks
-Brake calipers
-Pressure plates
-Lower arms

Other automotive parts
-Vanes for air compressors
-Shoes and shoe discs for air conditioning systems
-Vanes for power steering systems
-Noise-control sheets
-Radio-wave absorption sheets
-Saturation-resistant, noise-control cores
-Compact concatenated noise suppression cores
-Split noise-suppression cores
-Plastic gears
-Plastic cases


Nov. 1927 Rikagaku Kogyo was established. This company was the first to start manufacturing practical rings in Japan.
Dec. 1949 Reestablished as Riken Kashiwazaki Piston Ring (Headquarters at 3-5 Nihonbashi, Chuo-ku), capitalized at 20 million yen.
May, 1952 Listed on the Tokyo Stock Exchange.
Oct. 1979 Corporate name changed to RIKEN Corporation.
Oct. 1998 Received the TPM first-class prize for continuing excellence
Aug. 1999 Provided technical assistance to DANA-ALBARUS (Brazil) for piston rings for VW Brazil
May, 2000 Signed a memorandum of understanding with Dana (USA) for a global tie-up in the piston ring business
Mar. 2001 RIKEN's piston ring manufacturing facilities in Kashiwazaki, Japan and Kumagaya, Japan received ISO14000 certificates.
Feb. 2003 Established the Jakarta representative office as a subordinate organization under the Asian sales team of the overseas sales division.
Jan. 2004 Established Riken Automobile Parts (Wuhan) Co., Ltd. in Hubei, China to manufacture and sell piston rings etc. in China.
Oct. 2004 The Company's piston ring division and the precision machinery component division at the Kumagaya plant received ISO/TS16949 certification in October 2004. (The Company's main domestic and overseas subsidiaries received ISO/TS16949 certification around October 2004.)
June, 2007 The Company and MAHLE GmbH signed a memorandum of understanding under which they will form a global business alliance in the areas of piston rings, camshafts, and other products.
Jan. 2008 The Company sold all shares it owned in Riken of Korea Inc. As a result, the Korean company will be removed from the Group's consolidated statements from fiscal year 2008.
June, 2010 Formed an Overseas Committee designed to promote business strategies outside Japan based on a cross-section of operations.
Aug. 2012 Established Riken Mexico, S.A. DE C.V. as a production plant to supply automotive and industrial machinery parts to North, South, and Central America; in Aguascalientes.
Aug. 2014 Sold entire 100 percent stake of Riken Espana, S.A., and removed it from its consolidated financial statements.
Aug. 2014 Moved its headquarters to Sanbancho, Chiyoda-ku, Tokyo.
Oct. 2014 Jointly with Amtek India Limited, the Company established Amtek Riken Casting Private Limited in Rajasthan, India to manufacture and sell automotive castings.
Apr. 2015 Signed an MOU with KS Kolbenschmidt (based in Germany) that covers global sales, engineering, and development of power cylinder systems that includes pistons and piston rings.
Spun off the sealing ring business of Riken Automobile Parts (Wuhan) Co., Ltd., establishing it as Riken Sealing Parts (Wuhan) Co., Ltd., in order to strengthen the sealing-ring business in China.
Oct. 2015 Established Riken Sales and Trading (Thailand) Co., Ltd. in Bangkok, Thailand, to strengthen sales of piston rings in Asia.
Apr. 2017 Formed a business alliance of the camshaft business with Brother Precision Ind. Co., Ltd. and set up Riken Brother Precision Industry Corporation in Chiryu City, Aichi Pref.
Nov. 2018 Liquidated Allied Ring as a result of environmental changes taking place in the automotive-industry.
Jun. 2019 Established Riken Power System (Nanjing) Co,. Ltd., a joint venture with Nanjing Feiyan Piston Ring Co., Ltd., to manufacture and sell piston rings in China.
Apr. 2022 Moved from the First Section of the Tokyo Stock Exchange to the Prime Market due to the TSE's reorganization.
May 2023 Turned JFE Tsugite Co., Ltd. into a consolidated subsidiary, renaming it Nippon Pipe Fitting Corp.
Jun. 2023 Agreement reached at general meeting of shareholders on plan to merge with Nippon Piston Ring Co., Ltd. and transfer stock shares.

Supplemental Information 1