The Nikkei 225 Index was down 0.4% at 41,655, as of 0145 GMT. The broader Topix, which hit an all-time high on Thursday, dropped 0.5% earlier in the day.
The trade deal, announced late on Tuesday by U.S. President Donald Trump, reduced a reciprocal tariff on Japanese goods and autos-specific levies to 15% from the 25% Washington had threatened previously.
Shares of industrial robot maker Yaskawa Electric dropped 5.3%, shedding a steep three-day advance. Mitsubishi Motors plunged 8% after the automaker reported an 84% drop in first-quarter operating profit.
A Nomura Securities analyst said there were signs the market was “overheating.” The Nikkei’s 14-day relative strength index (RSI), a technical measure for an investment momentum, reached 77.8 on Thursday, the highest since the stock gauge hit its all-time high of 41,889.16 in July 2024.
There were 60 advancers in the Nikkei index against 164 decliners. The largest losers by percentage in the index were Shin-Etsu Chemical, down 9.2%, followed by Mitsubishi Motors. The biggest gainers were motor maker Nidec, up 2.6%, followed by chip industry supplier Disco, which rose 2.5%.