Prime Minister Yasuhiro Nakasone has made a hit in Japan with "photo line diplomacy" at the economic summit by maneuvering to be photographed next to President Reagan in the lineup of national leaders.

Nakasone's ability to be front and center in the camera view has political significance in Japan because his predecessors, often ill at ease and lacking in English-language skills, were frequently shunted to the ends of the line when summit leaders posed for pictures.

When the leaders were lining up to pose for their first group photograph before the dinner at Carter's Grove mansion Saturday night, Nakasone suddenly walked up and engaged Reagan in conversation.

He was chatting with the president when photographers interrupted for the picture, and thus was photographed next to Reagan in the lineup of summit leaders.

Nakasone managed a similar feat on Sunday morning by engaging the attention of British Prime Minister Margaret Thatcher, ending up between Thatcher and Reagan in a group photo of the leaders. Yesterday he managed to be photographed again next to Reagan as the leaders sat in a line of lawn chairs before a luncheon at Bassett Hall.

The photographs were transmitted by the Japanese press to Tokyo, where they have been among the most discussed aspects of the summit.