Share prices closed sharply higher, with the blue-chip Nikkei index at a six-week high, led by brokerage shares, following a rise in equities markets around the world, dealers said. Dealers said the strength of the US dollar, which was hovering around 116.20 yen shortly after the close of equities trading here, having touched 115.87 yen in New York late Friday, supported the stocks of exporters. Brokers said offshore investors also bolstered the market, having been net buyers of 11 mln shares today, compared to 3.6 mln Friday. The Nikkei 225 Stock Average closed 285.07 points or 1.7 pct higher at 16,624.80, its highest finish since Feb 7, when it ended at 16,720.99 The broader-based TOPIX index of all first-section shares rose 24.24 points or 1.5 pct to 1,688.22. Gainers overwhelmed losers 1,421 to 218, with 55 issues unchanged. Volume rose to 1.66 bln shares from 1.53 bln on Friday.