Of course, you can also fly, but once you factor in getting through security, the cost and time are about the same as the train. Meanwhile, if you get a ticket for unreserved seating, you can take any bullet train at any time within your allocated day. If you do so, remember to get on a Nozomi, as it makes the least stops (though it also has the least unreserved seating) and gets there in about two and a half hours. Don’t make the mistake of getting the Kodama, though, which takes almost twice as long!

Once you get to Osaka there are a number of things to do. Although Osaka is a big city, you’ll find it feels much more relaxed than ever-alert Tokyo.

A good first stop is Osaka Castle (大阪城・Osaka-jo). If you’re used to Western castles, this one might come as a shock, as the architecture has a very different style. Renovated in 1997, the bright-white castle is adorned with beautiful gold and green roofing. Entry to the castle grounds is free, and for ¥600 you can head to the top of the restored keep for stunning views of the surrounding city, as well as taking a look around the museum contained within.

Another great attraction, located on the edge of Osaka Bay, is Osaka Aquarium Kaiyukan (海遊館・Kaiyukan). Although it’s a little pricey at ¥2,300 per person, it’s a large aquarium holding some 30,000 creatures of 620 different species, and if you bring a camera you can entertain yourself for hours!

For a total of ¥3,000 you can also buy a joint ticket for the aquarium and the giant Tempozan Ferris Wheel (天保山大観覧車・ Tempozan Dai-kanransha) next door, offering a great chance for some scenic viewing 112.5 meters (369 ft) in the air!

If you’re looking for a more adrenaline-packed adventure, head to Universal Studios Japan (USJ) and have a go on the fast-paced rides. Though some, such as the Flying Dinosaur, are not for the faint of heart, others combine a more basic rollercoaster with immersive 4-D effects for a less terrifying experience.

Using domed screens, Harry Potter and the Forbidden Journey takes you on a flight around Hogwarts, where you can feel the hot breath of a dragon on your face as you make a narrow escape. The Wizarding World of Harry Potter is itself one of the highlights of the park for fans, and you might forget you’re in the heart of Japan when walking through the snow-topped buildings with butterbeer in hand!

Amid all your Osaka sightseeing, don’t forget to try takoyaki octopus balls and savory okonomiyaki pancakes, two foods this city is famous for! If you're looking for an easy recommendation, Takoyaki Doraku Wanaka (たこ焼き道楽わなか) is a famous brand that serves both dishes, with a number of branches around the city.

These are just some starting points for a short break in Osaka. Whenever you visit, you'll find there are plenty of unique experiences waiting for you!