Knowing if you can get married is based on the law of your home country and the country of your fiancé. However, the procedure is no different for two Japanese citizens who want to get married. It is also not impossible for an overstay to get married in Japan.
The law of one’s country determines whether they can get married or not. Japanese law can tell whether a Japanese citizen can marry or not, wherever country his/her partner comes from, and vice versa.
But, for people from other countries who are allowed to have multiple marriages, the other marriages will not be recognized in Japan because that is against their public order and moral.
If you get married in Japan, the marriage process will be based on Japanese law. The first thing to do is to submit the marriage registration to the local office.
For Japanese citizens, it is easy to know if they can get married when they look at their family registry or what the Japanese calls Koseki tohon. The foreign citizen must submit a “certificate of legal capacity to contract marriage” proving that you can get married. Pass it along with your marriage registration.
You both must sign the marriage registration to make your marriage official.
There are other foreign citizens who come to Japan with residency. This is for short-term residence in Japan. However, many of them continue to live in Japan even though it has expired – they are overstay.
Overstays are also legal to marry in Japan. Not in all cases, the embassy or consulate issues a “certificate of legal capacity to contract marriage” to a foreign citizen, so it is best to prepare other alternative documents.
It is necessary to prove that marriage is real and not just to prolong your stay in Japan. There are overstays who get married just to stay in Japan, but the relationship is not real.
Once the Immigration has proven and found that the marriage is real, then you can be given the status of residence “Spouse of Japanese national”. However, it may take some time.