I don't really want to argue with you, and I'm sure that what you are saying is what the recruiter told you, but based on my nearly 20 years of experience being a professor at a couple of different Japanese universities, either the recruiter doesn't know what he/she is talking about, is telling you what he/she thinks you want to hear, i.e. lying to you, or the institution that he/she is recruiting for is unlike all the other universities here in Japan.

the advisor said they're pretty slack with attendance. So long as you do your assignments you don't really have to show up that often.

This is the exact opposite. Japanese universities are strict on attendance, but lax on assignments. Students don't have to do very much studying as long as they show up. The basic attendance policy for universities comes from MEXT (the ministry of education) and is follows: * All classes must meet 15 times. If a professor has to cancel (for example if they get sick) they must conduct a make-up class. This is a requirement because: * All students must attend at least 2/3 of all classes. If a student does not attend 2/3 of all classes, they are not allowed to take the final exam. Basically this means that out of 15 classes the student must come to 10. Not being allowed to take the exam, means not being able to pass the class. The majority of classes are heavily weighted to the final exam. * If a student meets the attendance policy, they are allowed to request additional assignments and/or exams and can request to have their grade changed (by retaking the exam, or doing additional assignments) for up to one year after the class has ended. These are the minimum rules set by MEXT and some universities, and some departments, are stricter than that. General education classes usually follow the MEXT rules, and classes students take in their majors are stricter, for example 3/4 attendance policies.

The ratio of in-class to out of class study is also very different. At a typical western university, the ratio is 1 to 3. That is to say for every hour a student is in class, they will need to three hours of studying on their own (reading the textbook, researching additional information, writing papers, etc.). At a typical Japanese university the ratio is 1 to .3. For every hour in class, students are expected to do 20 minutes of study. Since classes are 90 minutes long, that means 30 minutes of self study and depending on the level of the university, most students don't even do that.

Age is just a number when defining maturity so it varies for everyone when it comes to that.

Again, this is categorically not true. Students do not become adults until they are 20, so the university has a LEGAL obligation to care of them because they are minors. There are lots of ways that this happens, but some of the best examples are dorm rules. Students have a curfew. Typically, 10 or 11 pm, but varies according to the city and/or prefectural laws. (Exceptions can be made, but require official permission from the division of student affairs.) Students are woken up at 7 am (regardless of what time they went to bed) and have to do the NHK calisthenics, every morning except Sundays. They are required to eat both breakfast and dinner at the dorm, regardless of their schedule. They have room inspections to make sure that their rooms are 'healthy' and, of course, they are not allowed to have visitors in their rooms, especially those of the opposite sex.