This weekend, the inaugural Pottery on the Hill event brings 15 of the most renowned potters in the United States to the Hill Center at the Old Naval Hospital, which opened to the public last year. The focus of the show is on the practical side, and the organizers’ concept was simple — fewer artists, more pottery. The intimate setting offers visitors the opportunity to see 100 or so practical vessels from each of the potters’ collections. The idea is to present useful products such as teacups, bowls, casserole dishes and coffee mugs. This is not a show for sculpture pieces.