When Japan returns to China by boat, Qingdao Customs and Shanghai Customs (at present, only Suzhou in Osaka, Shanghai, Kobe Yanjing in Tianjin, Rose in Nagasaki, Shanghai, Taicang in Jiangsu and Shimonoseki are closed) will conduct spot checks on luggage, especially when foreign students carry too many things.

The most important thing is yours: a box full of delicious food. What's delicious? Fresh food, meat products and dairy products are not allowed. In principle, milk powder is not allowed. Regarding milk powder, it is stricter than the airport.

Of course, it doesn't matter if you don't spot check. For details, please refer to the baggage regulations of the ideal country number Qingdao to Shimonoseki (see resources link).