TOKYO May 23 (Reuters) - The Nikkei share average plunged 7.3 percent on Thursday, its biggest one-day percentage drop in two years after weak Chinese factory data rattled investors, prompting them to take profits from a recent rally buoyed by massive Bank of Japan stimulus measures.
The Nikkei ended 1,143.28 points lower at 14,483.98, a two-week low. It was the 11th-largest point drop on record.
The Osaka Securities Exchange briefly suspending trade in Nikkei futures in the afternoon due to steep declines.
Trading was volatile. The benchmark had climbed to a 5-1/2-year high earlier in the session.
The broader Topix index sank 6.9 percent to 1,188.34, with a record high 7.66 billion shares changing hands.
As stocks dropped sharply, investors sought safety in government bonds, with the 10-year Japanese government bond yield down 6 basis points at 0.825 percent.
The 10-year yield hit 1.00 percent in the morning session, its highest since early April last year.