Kawakin dampers met national rules, failed contracts — so staff rewrote the test data

On October 16, 2018, KYB admitted shipping seismic dampers that failed ministerial certification, touching nearly a thousand buildings. Five days later, Kawakin Holdings reported to the transport ministry that its own subsidiaries — Koyo Seiki, which manufactured oil dampers, and sales arm Kawakin Core-Tech — had shipped dampers whose damping-force deviation exceeded the tolerances customers had contractually specified, and that inspection data had been rewritten to sit inside the allowed band before shipment. The affected shipments spanned February 2005 to September 2018.

The numbers were modest next to KYB's: six base-isolation dampers in two Tokyo and two Osaka buildings, and 1,423 vibration-control dampers across 89 buildings in 26 prefectures — schools and offices among them. There was a technical difference that mattered: Kawakin's products stayed inside the ministerial certification tolerance of plus or minus 15 percent, failing only the tighter contract windows of roughly plus or minus 10 percent. The fraud was aimed at the customer's spec sheet, not the building code.

MLIT issued a written instruction covering the full playbook: candid explanations to owners, performance-impact verification confirmed by third parties by year-end, replacement to the last building and last unit, a root-cause report, and 100 percent third-party-witnessed testing of every future shipment until the ministry judged its quality management fixed. The ministry also pulled forward its deadline for all 88 certified damper makers to report similar fraud; the internal surveys surfaced no further cases.

1,423 vibration-control and 6 base-isolation dampers in 93 buildings failed customer specs; MLIT ordered replacements and full third-party-witnessed retesting.

Quality control was designed to look right at shipment: inspectors could rewrite measured values into the contractual window, and nothing downstream re-measured the devices once installed.

The customer's tolerance was tighter than the law's, so a real shortfall against the contract felt invisible to regulation — management chose concealment over renegotiation or rework.

The company admitted it only grasped the actual state of its inspection process when it ran the survey forced by KYB's scandal; the QA system was never institutionalized.

As a latecomer damper maker competing on delivery and price, Kawakin treated failing units as a scheduling problem rather than a stop-shipment event.

A peer's scandal is the cheapest audit you'll ever get: five days of self-checking found what a decade of QA missed. If data only has to look right at shipment, someone will make it look right.

Replacements and re-verification ran under the ministry's instruction, with third parties confirming the seismic-performance impact on affected buildings. The accelerated industry-wide survey of 88 certified makers reported no additional fraud beyond KYB's and Kawakin's. No fine followed — MLIT's levers were instructions and shame — and Kawakin continued as a mid-tier maker, but every future shipment faced full third-party-witnessed testing until the ministry was satisfied. The episode settled into the 2018 damper file as the second domino: smaller than KYB, different fraud, same root.