Business class seat numbers are divided into AC and F, where A is by the window, C is by the corridor, and F is by the window and corridor;

The seat numbers of first class seats are AC and DF, where A and F are near the window and C and D are near the corridor;

The second-class seats are numbered ABC and DF, where A and F are by the window, C and D are by the corridor, and B is in the middle of AC. To sum up, seats A and F must be by the window.

Generally, the second-class seat of the bullet train is a window seat with the tail numbers 1, 6, 5 and 0, while the first-class seat is a window seat with the tail numbers "multiple of 4" and "multiple of 4+1", and 15 does not face the window.