There are different ways to seek a release depending on the phase of your detention.
If it is after the arrest and before the relevant court makes a decision regarding detention, the strategy would be to prevent the detention by submitting a written opinion to the public prosecutor to the effect that such request should not be made or by submitting a written opinion to the court to the effect that such request should be rejected.
If the court has already made a decision that you should be detained, you may file an objection under the quasi-appeal (jun-kokoku appeal) system.
If you are already prosecuted, you may seek your release through the bail system. If bail is granted by the court, you will be released on condition that you deposit the bail bond. A request for bail is more likely to be approved than a quasi-appeal before prosecution, because in most cases, the investigation has been completed by this stage. The amount of bail bond differs depending on the case, but it is generally between ¥1.5 million and ¥3 million.
In any case, in making a decision whether to release the suspect/accused or to continue the detention, the court will consider various factors such as: the possibility of destruction of evidence, the threat of escape, and the severity of the case. When seeking a release, it is important to show that there is no possibility of destruction of evidence or escape by submitting a letter of undertaking from a family member or a written oath made by the suspect/accused.
If the accused is a non-Japanese, it is possible that bail will be granted upon condition that the defense counsel keeps the suspect’s/accused’s passport or upon other conditions in order to prevent the accused from fleeing Japan. When the suspect/accused is a foreigner without a status of residence, he/she will be principally detained at an immigration detention center upon release, and bail will not be granted.