This would have taken place in 2013/2014 or around there. That was BEFORE the reforms that created the 4-year age gape safe harbor so maybe not. (BTW, depending on birthday timing 4 years would still allow a 1st year university student to bang a 3rd year middle schooler...)
I found this so now it's not so hard to figure out these sex crime conditions.
What you need to know about the revision to Japan's sex crime law
Apparently before, sex was considered "consensual" unless physical coercion or violence was present. Unless the drunk/drugged girl being passed around was resisting and was overpowered it wasn't rape at the national level.
The legislation also criminalizes nonconsensual sexual intercourse where physical coercion or violence is absent, taking into consideration various factors affecting the victim's ability to consent, such as a power imbalance, that were previously deemed as being difficult to prove.
Use of violence, intimidation, alcohol, drugs, or economic or social status are among the factors that will be considered when determining whether an act is consensual. Cases in which a victim has a mental or physical disorder can also be deemed nonconsensual.
New crimes will also be established to punish the act of secretly photographing or filming a person’s sexual anatomy, as well as providing such photos or videos to a third person, with perpetrators of either subject to imprisonment of up to three years or needing to pay at least ¥3 million ($21,170) in damages.
Those who distribute such photos or videos to a large number of unspecified people will have to serve a prison sentence of up to five years or face a maximum fine of ¥5 million.
...
How does the bill address cases involving individuals age 13 to 15?
While the bill criminalizes sexual intercourse with children under the age of 16, it allows an exception for consensual relationships involving an individual between the ages of 13 and 15.
In such cases, there will only be a punishment if the age difference between the individuals is five years or more.
