TOKYO, June 21 (Reuters) - Japan's Nikkei share average reversed course to close higher on Wednesday, as investors scooped up cheap heavyweights, with SoftBank Group and chip-related shares leading the gains.

The Nikkei index climbed 0.56% to end higher at 33,575.14, after falling as much as 0.7% earlier in the session.

The index initially tracked Wall Street slump, driven by profit-taking in the wake of a sustained rally amid signs of a weakening global demand.

Japan's broader Topix also recouped lost ground to end 0.5% higher at 2,295.01.

"After seeing the early declines, investors boosted their appetite to buy stocks on dips," said Shoichi Arisawa, general manager of the investment research department at IwaiCosmo Securities.

"This appetite will keep Nikkei's momentum, and the index looks set for a climb in the near term, but gradually."

Shares of SoftBank Group rose 3.68% and were the biggest boost in the Nikkei, after the technology investor held its annual general meeting on Wednesday.

CEO Masayoshi Son said that his tech investing conglomerate plans to shift its stance to "offence mode" amid excitement over advances in artificial intelligence.

Chip-related shares rose, with Advantest and Tokyo Electron climbing 1.25% and 2.8%, respectively.

Japan Airlines rose 3.43%, lifting the airline sector by 3% to become the top gainer among the Tokyo Stock Exchange's 33 industry sub-indexes.

The railway sector gained 1.63%.

Insurer Tokio Marine Holdings rose 2.57% after losing 5% in the previous session. The insurance sector rose 2.73%.

Silicon wafer maker Shin-Etsu Chemical lost 1.5% to weigh on the Nikkei the most.

Of the Nikkei components, 156 shares rose and 66 fell, with three being flat.

(Reporting by Junko Fujita; Editing by Sherry Jacob-Phillips)