Long ago, before he rose to prominence in the New York wine world, Daniel Johnnes, traveling through France, was drawn to the camaraderie that he felt among wine-makers and their friends when they sat down to eat and drink. Mr. Johnnes had a dream that some day he would find a way to recreate that social glow back in his hometown of New York.

How well he had succeeded was apparent last Monday at BYOB night at Montrachet, the unfussy pioneer of TriBeCa dining that is celebrating its 20th year on West Broadway. Though summer Mondays can be slow, the restaurant filled quickly, as customers arrived with their bottles of wine. Some of their choices would be priced in three figures on Montrachet’s wine list, or any other. The couple sitting across from me, for example, was sipping Chateau Trotenoy, 1990, a distinguished Pomerol worth more than the price of their dinner. Mr. Johnnes, the restaurant’s wine director almost since it opened, not only invites you to bring your choice of wines on Mondays but forgoes any corkage charge.

But saving money on wine is only the half of it. What’s striking about BYOB night at Montrachet is how naturally perfect strangers warm to sharing their wines. Within moments of being seated, the couple at the table adjoining ours was sharing our bottle of white Morey-Saint-Denis and we were trying their pink Bandol and red Cahors, bottles that they’d brought back from a vacation in France. I counted 12 wine glasses on our two tables, and that was less, per capita, than on some other nearby tables. Where big reds were being served, multiple decanters also crowded the tables. Dishwashing machines must wear out fast at Montrachet.

Mr. Johnnes, 50, a compact man with dark bristly hair, circulated among the tables, chatting and sampling the wine. Earlier in the day, Mr. Johnnes had told me, “I’m a Francophile. To me, the great Gallic experience is sitting around the table with lots of conviviality that is unrivaled. It’s something so entrenched in their culture.” A pretty good facsimile of what he described was on display that evening.

If you can’t make it to BYOB Monday, you can still take advantage of the restaurant’s BOBO (Bring One, Buy One) policy on Tuesday through Thursday. And Mr. Johnnes has yet another ploy to enliven the Montrachet wine experience: A game called “What’s My Wine?” It starts when you ask Mr. Johnnes or sommelier Troy Kinser to secretly choose a wine, specifying only color and price range. Players are given a scorecard listing six questions that must be answered after blind tasting the wine: Country of origin, region, appellation, major varietal, vintage, and producer. For each correct answer, 20% comes off the price of the wine. Get five out of six right, and it’s free. So far, only one diner has answered all six correctly. One who got five was Lettie Teague, executive wine editor of Food & Wine magazine. She bested her husband, food critic Alan Richman, who correctly guessed four out of six. The wine was a Savennieres, Coulee de Serrant 1996, from the Loire region of France, made from Chenin Blanc grapes by Nicolas Joly. Your columnist promises to play “What’s My Wine?” before long and to report the results, for better or worse (probably worse).

The downside of the game for the staff, Mr. Johnnes said, “is that it requires somebody to take extra time out of service to other tables.” The upside is that “if you can enhance the interaction with the customer, it’s a better experience,” and not only for the customer: “After 20 years here,” Mr. Johnnes said, “you try to keep the staff as well as the clientele feeling excited and also a little bit innovative.”

Montrachet’s wine list, as one would expect, is heavy on epic Burgundies. Bordeaux also carries weight, not least Chateau Latour-a-Pomerol 1961, considered to be outstanding even in a legendary vintage, at an eye-popping $10,000. Sounds to me like a pleasurable way to money launder. At the other extreme, a bottle of Morgon, Domaine Jean Descombes 2002, a top-of-class Beaujolais at $22, is a steal. Few restaurants at Montrachet’s level offer any bottle at that price, let alone a wine of matching stature, but they should.

Many selections on Montrachet’s list are imported by Jeroboam Wines, whose president is none other than Mr. Johnnes. “The seeds of my company go back to 1989, when a friend told me he was getting a federal importer’s license,” Mr. Johnnes said. “He said he’d clear some wines [through customs] for me, so I went to France to pick the first batch. It was a bit entrepreneurial, but I wanted to make our wine list extra special.” Some Jeroboam wines are wine royalty, such as the Meursaults of Comtes Lafon. Others are more modest, including several under the red-and-white “Petit Chapeau” label, which represent, Mr. Johnnes said, “my feeble attempt to make my own blends.”

Mr. Johnnes travels about five times a year to France to check out new wines and “get a feel for the latest vintages.” That means he’s away from Montrachet, as well as from his wife and two young children in Brooklyn, but he says that his boss, Drew Nieporent, whose Myriad Restaurant Group includes Nobu, Tribeca Grill, and the new Centrico, “has been very supportive of what I’m doing.”

Multiply that Monday night Gallic glow at Montrachet a few hundred times, and you’ll approximate what it feels like to experience La Paulee, a wine-sharing dinner that is the climax of three days of post-harvest celebrations held each November in Burgundy. “I wanted to do something to express that same spirit on a large scale in New York,” Mr. Johnnes said. “So in 1992 I brought over around a dozen vintners and some folk singers to do a local version of La Paulee. I lost a fortune but the event took root.”

Last March, 17 Burgundian vintners and a cadre of musicians arrived for the most recent La Paulee de New York, held at the W New York hotel. An afternoon grand tasting flowed into an even grander dinner, where guests mingled their own prize Burgundies with bottles brought by the vintners. At $1,250 a ticket, La Paulee was expensive, but many of the wines served, like those from Domaine de la Romanee-Conti, were valued in that range, if they could be found at all at retail. Dinner was prepared by Daniel Boulud and by Michel Richard of Washington’s Citronelle. The event was capped by an auction benefiting Meals-on-Wheels. Mr. Johnnes no longer loses his shirt on the New York version of La Paulee.

The next La Paulee de New York, held biannually, comes in 2007. I’m planning to go. With so many superb wines sure to be shared, I intend to train hard and well on BYOB Mondays at Montrachet.

Montrachet, 239 West Broadway, 212-219-2777, www.myriadrestaurantgroup.com. Dinner Monday through Saturday, lunch on Friday only. Closed Sunday.

Wines Recommended by Daniel Johnnes

PETIT CHAPEAU COTES DU RHONE 2003 ($12) Pepper and plum aromas, a bit chewy, with a touch of licorice in the background. Exactly what a basic southern Rhone wine should be – tasty and fleshy but not a heavyweight. At Crush Wine Co., 153 E. 57th St., 212-980-WINE.

CHARDONNAY, POUILLY-FUISSE 2001, DOMAINE ROMANIN So many wines with Pouilly-Fuisse on the label don’t justify their cost. This one, from old vines, delivers with an intense, bright, minerally core of flavor. At its peak now, a great wine with soft-shelled crabs. $10 a glass at Montrachet.

CHINON 2003, OLD VINES, PHILIPPE ALLIER ($30) Loire reds made from Cabernet Franc can undesirably taste of green peppers in cool vintages. In the brutally hot summer of 2003, Cabernet Franc ripened to plushness in the Loire wine region. Plums and even chocolate wiped away that green stuff. A yummy wine. At Crush Wine Co.