Kanemasu is well off the beaten path of most well-known Tokyo restaurants on a literal island that is Tsukishima just east of Ginza and Tsukiji market. There's not much to see on this man-made island but Kanemasu (and if you're feeling adventurous, Monja Street *add monja street link*) is well worth the trek. Despite its out-of-the-way location, you will be faced with lines no matter what time you show up and when you finally get inside, you'll see the reason for the constant queue. The place is about the size of a large closet with the kitchen and bar taking up more than half of the already tight space. Don't even think about walking in there with armfuls of shopping bags or a massive backpack because there's just no room. So travel light when headed there and keep your crew small or you may need to leave a man behind.
The only menu is a chalkboard with scribbled dishes that even locals have a hard time deciphering. If you don't speak Japanese make friends with your barmate to help you order or come prepared with memorized dishes. Or if you are completely unprepared, just point to the unintelligible scribbles (better yet, just point to the picture on Black Buddha) and just trust that you'll get something indecently delicious. The one thing that you need to make sure you know how to order though is the famous meat sushi. The wagyu beef sushi topped with uni is so rich you'll go broke just looking at it and then you'll eat the luxurious morsel and cry a little that you can't eat this little miracle every day. Other highlights include head-on prawns, GARGANTUAN oysters (we're talking a three biter here), hairy crab salad and a succulent, melt-in-your-mouth short rib stew. The menu changes depending on seasons so some dishes might be temporary (except for their signature beef and uni sushi) but with its proximity to Tsukiji market, you can't go wrong with any of their seafood dishes.
Given the tight space and lack of seating, Kanemasu isn't a place to dawdle and nurse your beer or soak in the ambience. Get in, stuff yourself with glorious wagyu, uni and seafood, pound some cold brew, get out.