Shinjuku isn’t for the faint-hearted. But if you’re new to Tokyo and want a crash course in crazy, it’s the first place you should come to. Sure, Asakusa has more history and Roppongi has better nightlife, but neither can compete when it comes to dealing out high-voltage culture shocks. On the west side of Shinjuku station, which heaves with commuters and the smell of strong espressos, things are typically well-ordered. This shimmering business district is home to some of Japan’s tallest skyscrapers (as well as more than 13,000 bureaucrats) and there are enough high-rise megastores to have you craning your neck in disbelief. It’s a hardworking part of the city, where success is measured by the number of hours you spend at the office, and exploring it for the first time feels like stumbling through an ultra-efficient city of the future. But cross to the other side of the train tracks, and things couldn’t be more different. Here, chaos rules. Under the hot neon lights of Kabukichō, in the eastern part of Shinjuku, you’ll find stand-up noodle bars snuggled next to strip joints and love hotels. Huge video screens pump noisy adverts into roadside bars, Blade Runner-style, and street hawkers skulk in the shadows by jazz clubs and theatres. To escape these guys, who’ll try anything to get at your yen, head to an all-night karaoke bar where you can croon until your sake-soaked vocal chords feel like they’re on fire. Or squeeze down the oddball alleyways of the Golden Gai district, which attracts artists, musicians and filmmakers with a ramshackle heap of more than 250 bars – each with its own unique theme. Chances are, you’ll still end up singing the night away. When the morning sunlight starts to extinguish Shinjuku’s nocturnal glow, you can take a stroll through the cherry blossom trees of Shinjuku Gyoen – Tokyo’s finest park – and give yourself a well-earned pat on the back. Consider yourself initiated.