I wouldn’t worry about buying advance tickets. As others have said, the line moves quickly. The real queue is waiting after you’ve passed the tickets area to go up the elevator.

Yes you can access the castle grounds free of charge. That's what I did! But you need to pay for admission into the castle, which might be worth it for the panoramic views.

No worries. Admission fee is for Castle. Credit and cash OK.

I have visited the Castle several times and always closes at 5pm so, if you arrive at 4pm you would have enough time. It opens at 9am.

Yes, the 600 yen covers everything. The Osaka pass is a pass that gets you into the main tourist attractions in Osaka for a lot cheaper than if you were to pay at each one of them separately. Worth getting if you're interested in going to at least 3 or 4 of the included sites.

Admission fee is 600 yen (about us$5). You can buy them at the main entrance.

There is no charge for children under 15 years old，but you need prove his age. Obviously a small child may not be necessary it.

Hello Zehra Yes I would visit the shine while you are there. If you have time visit the restaurants and tourist shops across the park from the castle. It gets busy but there are places to sit. If you have more time in Osaka you must visit Dotonbori you will have a wonderful food and people experience. Enjoy yourself in Osaka

The castle is open 9 to 5pm, though it may extend times during spring and summer.

I think it does. But perhaps today Monday 25th Christmas Day it may be close. Better ask by a phone call