A former employee of Sumitomo Corporation was sentenced Friday for illegally entering the U.S. Navy Yokosuka Base using a forged identification card [1].
The ruling highlights the security vulnerabilities of strategic military installations and the legal consequences of violating the Japan-U.S. Status of Forces Agreement [1], [2].
The Yokohama District Court sentenced Keitaka Mizuno, 46 [1], to 10 months in prison [3], suspended for three years [3]. The court delivered the verdict June 19, 2026 [3], following an investigation into an intrusion that occurred in October 2025 [1].
Mizuno previously worked for the major general trading company and had experience with U.S. defense equipment [1], [2]. He said his desire to enter a military base had resurfaced after he had failed in a previous attempt to enlist in the U.S. military [1], [2].
During the proceedings, Mizuno said his mindset during the incident was being in a "resort mood" [4]. The presiding judge at the Yokohama District Court said the defendant's criminal responsibility was not light [1].
The intrusion involved the use of a fraudulent ID to bypass security protocols at the Yokosuka facility in Kanagawa Prefecture [1], [2]. This breach of a high-security site is treated as a serious offense under the laws governing the presence of U.S. forces in Japan [1].
“The presiding judge said the defendant's "criminal responsibility is not light."”
This conviction underscores the tension between civilian curiosity and the rigid security requirements of the Japan-U.S. military alliance. By penalizing the use of forged credentials to enter a restricted zone, the court reaffirms that personal fascination or former professional ties to defense equipment do not justify the breach of international security agreements.
