Chablis is the most distinctive expression of Chardonnay in the world. That it happens to be my personal favorite shouldn't discourage anyone from exploring the grape more widely. The Chardonnay grown in Burgundy proper- around the villages of Puligny, Meursault, and Chassagne- tends to command much higher prices.
Chablis is grown in the same band of Kimmeridgian clay and limestone base that stretches from the White Cliffs of Dover through Champagne and down into Sancerre and Pouilly-Fumé. The soil is basically fossilized shellfish. Primordial oysters, clams, and the like.
Vieilles Vignes- "Old Vines"- is subjective, but I think the level of detail, nuance, and refreshment in this example puts it close to a Premier Cru. 40-70 year old vines here.
A cold glass of Chablis is a fine match for all seafood. It's also a great constitutional at the end of a long day. 100% Chardonnay. Serve cool to cold.