Compared to neighboring Shinjuku Station only two minutes away, Shin-Ōkubo Station is relatively small, with just one exit and only the JR Yamanote Line passing through. Billboards with Hangul (Korean language) letters line the platform, with one claiming that the nearby Seoul Ichiba food market is like having "Seoul City just 3 minutes away". With Korean cafés, Korean restaurants, Korean sweet vendors, and K-Pop fan goods sold at every corner, Shin-Ōkubo is Tokyo's answer to New York's Koreatown.
To visit the area with the most Korean shops/cafés/restaurants/food markets, just take a right after exiting the station and go straight. You'll invariably find something that catches your attention, whether it's sweet-smelling hotteok (a pancake-like dessert with various fillings) or the tempting thought of patbingsu (shaved ice with fruits and ice cream on top) melting on your tongue.
In 2011, Shin-Ōkubo Station was the third-least frequented station on the busy Yamanote Line that circles the central part of Tokyo and connects many of its most touristed areas. The recent popularity of K-Pop singers (TVXQ/Tohoshinki, KARA, Girls' Generation, etc.), however, has prompted an obvious increase in people-traffic: Shin-Ōkubo Station's one exit is always very crowded, with a steady stream of people trying not to bump into teens and tweens waiting for friends to arrive. The streets around the station aren't much better in terms of density, and trying to get somewhere in a hurry can be a pain on weekends.
But even with the crowds, a trip to Shin-Ōkubo is well worth it. The local restaurants are generally inexpensive, the sweets are exotic, and even if you don't know a thing about K-Pop, it's always fun to watch girls squealing with excitement over a photo of their favorite band.
So next time you're in Shinjuku, hop on the Yamanote Line. In just two minutes by train, you'll find yourself in Shin-Ōkubo. Alternatively, a 15 or 20 minute walk north following the train tracks will get you to this distinctive area on foot.