The benchmark Nikkei share average dropped 0.41% to 23,410.63. The broader Topix lost 0.86% to 1,617.69. For the week, the Nikkei was down 0.89% and the Topix lost 1.8%, with the latter being the largest drop in more than two months.
All but two of the 33 sector sub-indexes on the Tokyo exchange traded lower, with real estate, pharmaceuticals and land transport leading the decline on the main bourse.
Sentiment was weighed down after coronavirus restrictions were reimposed in Europe, with London entering a tighter lockdown and France imposing night curfews in major cities to curb a jump in COVID-19 cases.
Some investors also remained on the sidelines due to uncertainty over the U.S. stimulus talks, and ahead of the U.S. presidential election and earnings reports from domestic firms.
Turnover was subdued with only 1.859 trillion yen ($17.66 billion) of stocks changing hands on the main board, about 20% below the average over the past year.
On the main board, decliners outnumbered gainers by a ratio of roughly 7 to 2.
The Nikkei, however, was helped by gains in index heavyweight Fast Retailing, which jumped more than 4.4% after the operator of casual clothing chain posted better-than-expected earmings.
Fujifilm Holdings also jumped 2.5% after the company said it had applied for approval in Japan of its anti-influenza drug Avigan as a treatment for COVID-19.
The Mothers Index of start-up firms lost 1.66%, after hitting a 14-year high earlier in the week.