Tokyo - Tokyo stocks sank on a strong yen on Monday morning, with automakers and electronics firms taking a hit, while Toshiba dropped on a report that its troubled US nuclear unit could start bankruptcy proceedings this week.
The benchmark Nikkei 225 index fell 291.74 points, to 18 970.79 by the break, while the Topix index of all first-section issues was down 21.08 points, at 1 522.84.
Exporters sank as the yen strengthened against the dollar on growing doubts about US President Donald Trump's ability to carry out his economic agenda after Friday's failed healthcare deal.
The yen is seen as a safe bet in times of uncertainty or turmoil, but a stronger currency hurts the profitability of exporters - hitting demand for their shares.
The dollar slipped to ¥110.37 from ¥111.12 in New York on Friday.
"Markets are likely to start the week in a cautious mode," Rodrigo Catril, a currency strategist at National Australia Bank, said in a commentary.
"This was the first major attempt by the administration to reform the government and its miserable failure exposes the limits of President Trump's negotiating skills."
Trump's replacement for Obamacare was pulled Friday as he failed to garner enough support among Republican lawmakers, who have a majority in both houses of Congress.
Toshiba opened four percent higher before diving after the leading Nikkei business newspaper said its loss-hit US unit Westinghouse could file for Chapter 11 bankruptcy as early as Tuesday in a court-protected restructuring.
The firm went into the break 5.65% down at ¥210.4. The Nikkei said Westinghouse has turned to Korea Electric Power as a sponsor for its post-Chapter 11 reorganisation.
A Toshiba spokesman declined to comment on the report.
In other trading, Tepco fell 1.64% to ¥418 on a report that the Fukushima plant operator will shuffle its top management.
Toyota dropped 1.25% to ¥6 151 while rival Honda lost 1.74% to ¥3 380.
Sony fell 1.16% to ¥3 561, Canon dropped 0.91% to ¥3 463 and Panasonic edged 0.12% lower to ¥1 192.
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