A16, one of the best Italian restaurants in San Francisco, is a newcomer to yuppie-laden Chestnut Street swiftly nailed down its turf and acquired a devoted following. The secret is the basic, hearty and well-executed Southern Italian cuisine and an extraordinary list of Italian wines. The exterior and décor evoke the stylish, understated sophistication of New York’s SoHo, and the clientele lives up to the challenge. This is the heart of the Marina, meaning young, affluent, well-heeled, and good-looking types looking to hook up, if the paperwork fits. As for the food, the wood-fired pizzas make a strong showing, as do the pastas and meats. Simple is the toughest game of all, and both the food and the atmosphere succeed with classic simplicity at A16. Oenophiles come for pours by owner/sommelier Shelley Lindgren, an unmatched connoisseur of Southern Italian vintages. The young, trendy Marina District crowd gathers in this narrow contemporary space nightly, and increasingly competes with the magazine review set (older, not local) for reservations. Southern Italian cuisine with pizzas, pasta, and meat prepared alla Napoli is matched by one of the city’s most Italian and best wine lists.