If you have lost a passport, please get a proof of loss of passport issued by your nearest police station quickly. After this, you will have to carry out the procedures for having your passport reissued at the embassy or consulate of your country in Japan. When you do this, you will need the receipt number which is written down on the proof of loss of passport, so be sure to make a note of this or take a copy of the proof to the embassy or consulate.

Your personal information is written on your alien registration card, so there is a risk that somebody could be misusing this. In the event of losing your card, report the loss at your police station or police box as quickly as possible, and undertake the procedures for having a new card reissued at the administrative office of the municipality where you reside within 14 days of the day when it was lost.
If your alien registration card is torn, you will need to have a new one made. In this case, take the alien registration card that you have used up until now to your municipal administrative office, and carry out the procedures for having it reissued there (please refer to B Alien registration, 5-1 Application for reissue of alien registration card)

If you have lost your cash card, you should get a proof of loss issued quickly by the police. You should also get in touch quickly with your bank or credit card company and have transactions using the card suspended.

Please enquire at a police box or police station. In the event of forgetting or dropping your belongings in a train or bus, please enquire directly at the station master, train crew, or train operating company.
Information about forgotten or dropped belongings which have been taken to police boxes or police stations will be gathered together at each police station; if the person who dropped or forgot the item does not come to collect it within six months and two weeks, the item will become the possession of the person who reported the item. Please enquire as soon as possible at a police station or police box.