The act of intentionally or negligently parking on another person's land without the permission of the land owner or other right holder (illegal parking) is an act that illegally infringes on the rights or interests of another person, and is, in principle, considered illegal(Article 709 of the Civil Code).
If illegal parking causes damage due to interference with land usage revenue or parking services provided by business operators, the perpetrator will be liable for damages to the victim.

In the Supreme Court precedent (December 7, 1965, Minshu Vol.19, No.9, p.2101),
it is recognized that there are cases where self-help is permitted in certain cases. Based on this, multiple lower court precedents have subsequently affirmed self-help.

For example, on February 15, 2017, the Tokyo District Court held that regarding illegal bicycle parking,
"The defendant argues that the actions that the plaintiff claims to have taken, such as locking the bicycle's tires and moving it within the parking lot, are so-called acts of self-help, and it is sufficient to make the parking lot available for use, and that the plaintiff's further actions (tire locking) are unreasonable and cannot be acknowledged. However, since it is reasonable to try to recover the costs incurred when the bycicle parked in the parking lot was removed and stored, including such costs as damages should be considered to be within the scope of a considerable causal relationship."
Therefore there is a judicial precedent that affirmed the legality of tire locks for illegally parked bicycles.

Furthermore, according to the Kanagawa Shimbun and other publications dated February 4, 2022, it was reported that the Yokohama District Court towed a passenger car that had been abandoned in front of the exit of the Yokohama District Court building to a parking space behind the building.