About us

Message from the President

Contributing to the wellness of society by protecting structures, human lives, and properties with grout-filled rebar splices

Since its establishment in 1977, we, the pioneers of the grout-filled rebar coupler, have developed and released the NMB Splice Sleeve. The Splice Sleeve is ideal for the precast concrete construction industry, has excellent seismic resistance and fatigue performance, and does not require any personnel with special certifications to make the connection. We are proud of the great contribution we have made to the development of the precast concrete construction method in Japan, an earthquake-prone country.
Shortly After selling the first grout-filled rebar splices, we experienced the Great Guam Earthquake (1993) and the Great Hanshin-Awaji Earthquake (1995). We conducted a survey of precast structures under/after construction using our splices and confirmed that there were no structural damages at all.
In the year 2000, we developed and began the distribution of Slim-Sleeves for the cast-in-place construction method, and its application is steadily expanding. After subsequent natural disasters, the Great East Japan Earthquake (2011) and Kumamoto Earthquake (2016), we again surveyed the companies utilizing the Splice Sleeve and confirmed that there was no structural damage to any of them.
In many countries overseas, there are no earthquakes, but we will continue to focus on providing high-performance and high-quality services. Our sustainable growth is rooted in our joint research with universities in Japan and overseas, and by further promoting the expansion of NMB applications in around the world.
We strive to contribute tremendously to the world construction industry.

Shigetaka Kumagai
President & Director

Corporate History


















Splice Sleeve Japan, Ltd.(SSJL) was established to exclusively manufacture and sell the world's 1st Grout-filled mechanical coupler, NMB Splice-Sleeves.

NMB Splice Sleeves started dominating the primary market of 5-story precast concrete housing projects under the Housing and Urban Development Board (HUD) of Japan.

NMBs were first used in a high-rise application, the 30 story residence tower, Shin Kawasaki.

Splice Sleeve North America, Inc.(SSNA) was established as a California corporation in Sacramento.

NMBs were used in the construciton of the 30-story, 5000+ room MGM Grand Hotel in Las Vegas.

7.8 Magnitude Earthquake on Island of Guam, all projects using NMBs had no damage.

6.9 Magnitude Great Hanshin Earthquake on Kobe in Japan, all projects using NMBs had no damage.

Continuing global expansion, Splice Sleeve (S) Pte Ltd was officially registered and established in Singapore.

NMBs were used in precast columns in the 39-story Paramount tower, San Francisco.

NMB Splice-Sleeve was recognized as a Type 2 coupler by ICBO ER-5645 and NER-217.

NMBs were used in precast columns in the 56-story Shiodome H residential tower in Tokyo.

NMBs were used in high-strength precast concrete columns in the 59-story Park City Musashi-Kosugi residential tower near Tokyo.

NMBs were used in precast columns in the 50-story Singapore Public Housing Project, The Pinnacle@Duxton.

9.0 Magnitude Great East Japan Earthquake on Tohoku in Japan, all projects using NMBs had no damage.

7.0 Magnitude Earthquake on Kumamoto in Japan, all projects using NMBs had no damage.

NMB Splice-Sleeve system was tested to meet International Standard ISO15835 in Singapore.

NMBs were used in high-strength precast concrete columns in 100+-story Australia 108 in Melbourne.


  • Shigetaka Kumagai

    Shigetaka Kumagai

  • Raymond Chong

    Raymond Chong

  • Masahiro Abukawa

    Masahiro Abukawa

  • Masahiro Abukawa

    Akira Matsuguchi

Company Information

Company name Splice Sleeve Japan Ltd
Address 17-1 Nihonbashi Hakozaki-cho
Chuo-ku, Tokyo 103-0015 JAPAN
President Shigetaka Kumagai
TEL/FAX TEL 03-5642-6120
FAX 03-5642-6150