Tokyo stocks fell 0.93 percent in the morning session of Tuesday as investors locked in some of the previous week's steep gains.
The 225-issue Nikkei Stock Average was down 172.00 points from last Friday to end the morning at 18,266.67, reported Xinhua news agency.
Tokyo markets were closed Monday for a holiday.
The broader Topix index of all First Section issues on the Tokyo Stock Exchange shed 11.30 points, or 0.75 percent, to 1,503.83.
Decliners were led by mining, banks and transport equipment.