Kawasaki barred from bidding in Japanese Defence Ministry tenders due to engine data falsification

The Japanese Ministry of Defence (MOD) has barred local shipbuilder and engine manufacturer Kawasaki Heavy Industries (KHI) from participating in MOD-led bidding processes for a period of two and a half months from December 26, 2025.

The prohibition is a disciplinary measure imposed by the MOD on KHI after the latter admitted to having falsified performance data in connection with tests conducted on marine engines.

Earlier this year, an investigative committee of third-party lawyers found that KHI may have falsified data from fuel efficiency performance tests that it conducted on diesel engines to be installed on the submarines of the Japan Maritime Self-Defence Force (JMSDF).

A separate MOD investigation revealed that KHI had indeed engaged in long-term falsification of its inspection data. Although defence officials said that the engines' safety and performance were not affected, a number of engines that were tested had failed to satisfy key technical requirements related to fuel consumption rates and other parameters.

In a supplementary investigation report submitted to the MOD last August, KHI admitted to the falsification claims and explained that it had recorded target values rather than actual fuel consumption rates on engine test result sheets. The company said that it resorted to this measure over the course of 33 years from 1988 to 2021 to ensure the timely delivery of the engines.

An investigation also found that multiple departments across KHI were involved in the falsification of data related to 66 engines.

All but one of the 24 submarines currently in service with the JMSDF are fitted with KHI-built diesel engines. According to the MOD, the data falsification issues were identified on all 23 boats fitted with the KHI engines.