Alex C.
Yelp
Built in 1597, it was the largest castle at the time of construction, and intended to unify Japan under one rule. It was eventually burnt down due to war, and rebuilt by the new rulers in 1615. Part of the castle had burned down again several decades later, and was never fully restored until 1931, and entirely retrofitted with modern technology in 1997.
The very impressive castle is surrounded by several moats, walls, citadels and turrets. At the western end, you'll find Nishinomaru Garden with 600 cherry trees. It is a popular and beautiful spot to admire the cherry blossoms when the season is right (typically early April).
On the north side of Osaka Castle, you can find the golden ferry ships that you can board for a quick tour of one part of the moats. Tickets cost ¥1,500 / adult, and the trip is limited to a very small section of the northern moats where the boats are docked at. The novelty of riding the boat wears off quickly after you realize how little there is to see from the small section that the boat can access.
Ironically, Osaka Castle itself can be accessed for cheaper than the boat ride. Admission costs ¥600/adult, and children below the age of 15 can enter for free. The castle itself is very modern, with both elevators, AC and Wi-Fi. It consists of multiple floors, and you can actually go all the way to the top to get a nice view of Osaka. There are over 10,000 historical artifacts housed within the castle, which provides a deeper insight into the prominent role Osaka played in Japan's history. All displays have English plaques so foreign tourists can also follow along.
If you have an Osaka Amazing Pass, you can skip the long ticket line for Osaka Castle and get free admission. The pass also gives free admission to Nishinomaru Garden as well.