The dollar, which dropped below 105 yen in early trade, changed hands at 105.24 yen against the dollar in Asian afternoon trade from 105.39 yen in New York on Friday.
(File photo: VCG)
The greenback's fall came after US President Donald Trump said he is raising tariffs on Chinese imports.
Earlier in the day, the yen hit the highest level against the dollar since November 2016, when the US currency weakened on expectations of then-president-elect Trump's fiscal expansion policy.
"If the yen rises further, it's going to be serious for Japanese exporters," Okumura said.
"Trading is expected to remain sensitive for the rest of the week," he added.
The fall in Tokyo shares was led by exporters, with Toyota losing 0.67 percent to 6,869 yen and Nissan down 1.53 percent at 648.8 yen.
Nintendo dropped 2.83 percent to 39,820 yen as Sony fell 1.08 percent to 5,839 yen.
