If you lost your Individual Number Card
Please refer to the Individual Number Card general information site (https://www.kojinbango-card.go.jp/en/) and complete the necessary procedure. It is not necessary to contact the Health Insurance Society. If you undergo an examination during the period when you cannot use your Myna health insurance card, please use your digital Health Insurance Eligibility Certificate.

If you lost your Health Insurance Eligibility Certificate (a valid document assuming you received a paper copy)
Please contact the Health Insurance Society. Note that it is not necessary to file a loss notice for a paper-based Health Insurance Eligibility Certificate that has expired due to the expiration date being reached.

If you do not know your KOSMO Communication Web ID or other information necessary to have a digital Health Insurance Eligibility Certificate issued
Please see the KOSMO Web manual. https://secure.pwc-kenpo.jp/kosmo_web.jsp