Tokyo stocks retreated Thursday morning as investors opted to lock in gains after the market's recent rise, while initial jitters ahead of Prime Minister Shinzo Abe's Cabinet reshuffle later in the day have now been largely factored in.

The 225-issue Nikkei Stock Average dropped 76.04 points, or 0.38 percent, from Wednesday to 20,004.00.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, fell 5.11 points, or 0.31 percent, to 1,629.27.

Iron and steel, electric appliance and transportation equipment-linked issues comprised those that declined the most by the morning break.