"The best Mexican food in town," the hand-chalked sign outside Salsita proclaims. That's certainly a cocksure statement for a cantina of such modest dimensions. But, as we all know (in Japan better than anywhere else), when it comes to eating well, what matters is neither the size of the kitchen nor the length of the menu but quality, attention to detail and that plus-alpha personal touch. You'll find Salsita has that in spades.

Salsita owner-chef Koji Moriyama makes the most of his tiny open kitchen.

You can glimpse the bold facade of yellow, red and blue from the Yamanote Line, but behind that, Salsita is little more than a hole in the wall. The interior is equally cheerful, with walls and place mats in bright primary colors. But with its L-shaped wooden counter for 10, plus room for four more crammed round a table at the back, the configuration is that of the classic izakaya or koryoriya. And that's the way owner-chef Koji Moriyama runs it.

He's the serious guy you see hard at work in the tiny open kitchen, attending so closely to his food he barely acknowledges his customers as they arrive. You can tell he has paid his dues in Mexico by the artifacts arrayed along the counter: empty bottles of rare tequila; four types of chili sauce, none available outside North America; jars of dried chipotle chilies; a Day of the Dead statuette; even a cactus or two. At the same time, though, you can tell Moriyama is a trained chef (as opposed to a nostalgic ex-backpacker) by the way he moves, and the remarkable order and cleanliness of his kitchen.

It may be small, but Salsita serves good food.

The actual business of taking your order, delivering your food and (most importantly) mixing your drinks is left in the able hands of the friendly senorita who acts as Moriyama's assistant. She can provide beer, of course: Yebisu on draft; Sol (as piss-weak as Corona, but classier); tasty Bohemia lager; and the richer, amber-brown Negra Modelo in bottles. She can also construct a very adequate cocktail -- not just margaritas, mojitos and pina coladas but also interesting beer mixes such as Bull (Negra Modelo with a shot of rum and a wedge of lime). And, when the time arrives, there is a list of over half a dozen tequilas to choose from.

As you'd expect, you spend the evening at Salsita as you would at your local izakaya -- or indeed at any bar in Mexico -- ordering a couple of dishes at a time to go with your drinks, rather than mapping out an entire meal from the moment you sit down. What is unexpected, though, is the depth and range of the menu and the elaborate descriptions of each dish, both in Japanese and in English that is better than most gringos could muster.

Without fail, start off with some of Moriyama's excellent guacamole. He produces it to order, cutting up the avocados, coarsely mashing their green flesh, fine-tuning the seasoning until it has exactly the right taste and consistency, and serving it up with freshly made, crisp tortilla chips. You will be hard pressed to find better guacamole anywhere in the city.

Nor should you miss the homemade chorizo. Moriyama makes them with four different spices to give the sausages a good piquancy and doles it out piping hot from the skillet with potato and vegetable pickles on the side. It is exceptionally tasty.

And so are his tacos, his enchiladas and quesadillas. These latter also merit serious investigation. They are composed of two wheat-flour tortillas sandwiching a rich, gooey filling of melted cheese and small morsels of prawn (or, if you prefer, more of that same chorizo). To give an edge to the soft, mollifying texture, the wedges of quesadilla are adorned with chipotle chili and jalapeno pepper.

Vegetable matter does not feature prominently at most Mexican restaurants. So we were pleased to find a number of salads on the menu. In the Creole Salad, the salad greens are bolstered with egg, avocado, tomato and bell pepper, a combination both colorful and tasty.

We did not try the flautas ("flutes") -- deep-fried rolled-up tortillas stuffed with pork -- though they looked appetizing in the extreme. But we were so intrigued by the idea of a "zucchini pudding" that we put in an order. When it arrived, piping hot after 20 minutes in the oven, it turned out to have the texture of quiche, with pureed zucchini blended with molten cheese to form a super-rich filling.

Moriyama makes a very mean version of mole sauce, the dark chocolate cooked down with hints of chili and dried fruit. But even so, we were slightly disappointed with his chicken and mole poblano. Next to such richness of flavor, the white chicken meat seemed bland and tasteless, perhaps because it was from a flabby broiler rather than a fowl that had been allowed to run free through the pueblo.

This aside, everything we tried was first-rate, and we will be back to work our way through the rest of the menu. But we will probably wait until after the worst of the summer is over. It can get pretty hot inside Salsita, especially if you're sitting right next to the cooking area.

But that is a small discomfort, when there is such good food to be had. There's another sign outside Salsita that simply reads "Que rico . . ." As any linguist can tell you, that's Spanish for "Pretty damn good!"