(Fixes headline to indicate Nikkei erased gains, not pared them)
TOKYO, June 8 (Reuters) - Japan's Nikkei share average gave up early gains to close lower on Thursday, as the yen rose in a market already on tenterhooks about looming global events.
The Nikkei ended down 0.4 percent at 19,909.26, after climbing 0.1 percent in morning trade.
The dollar, which was up against the yen for much of the session, fell 0.3 percent to 109.50 yen, pressured by a report that the Bank of Japan was mulling how to communicate its eventual exit strategy from its monetary stimulus.
Caution reigned for much of the session, as UK voters head to the polls for a general election, the European Central Bank holds a regular policy meeting and former FBI director James Comey will testify to the U.S. Senate later on Thursday.
The broader Topix slipped 0.4 percent to 1,590.41, while the JPX-Nikkei Index 400 also fell 0.4 percent to 14,171.39.
Reporting by Tokyo markets team; Editing by Biju Dwarakanath