It is easy to buy tickets at the stadium, and is never sold out.
Tickets will cost 500yen more than if you buy them at a ticket machine in a convenience store.
The ticket office is at the top of the stairs which you come to walking up towards the stadium. After one flight of stairs you get to an area selling club merchandise with a large monument in the middle (this area is free to visit and see the entertainment on the day even if you didn’t go to the match).
There is then a second flight of stairs, at the top of which are 3 windows which sell tickets. Generally the queue is less than 2-3 people.
The cheapest tickets allow you to sit behind the goals. One goal is designated for neutral visitors and is very quiet, the other has some atmosphere from the home fans but no shade from the sun and rain.
The 2nd cheapest tickets allow you to sit on the far side of the stadium, and is where most fans sit. This area has the best atmosphere, especially on the corner of the stand next to the closest goal where the majority of the Ultras sit.
If you want to sit here the best way to get in is to go back down the stairs to the monument and walk behind the stadium to go into the back gate. This is also where most of the food and drinks shops are.
The most expensive seats are above the bench and gets you a seat rather than a bench, and gives you a view the same as if you were watching from television.
If you buy these seats then enter the stadium from the front doors 50m down from the ticket office.