The Nikkei index opened slightly lower Monday as investors locked in gains after the benchmark closed at its highest level in around 33 years late last week.
In the first 15 minutes of trading, the 225-issue Nikkei Stock Average fell 18.66 points, or 0.06 percent, from Friday to 30,789.69. The broader Topix index was up 0.05 point at 2,161.74.
Decliners were led by precision instrument, wholesale trade and electric appliance shares.
At 9 a.m., the U.S. dollar fetched 137.69-70 yen compared with 137.88-98 yen in New York and 138.11-13 yen in Tokyo at 5 p.m. Friday.
The euro was quoted at $1.1.0820-0824 and 148.98-149.05 yen against $1.0801-0811 and 149.00-10 yen in New York, and $1.0776-0778 and 148.83-87 yen in Tokyo late Friday afternoon.