TOKYO, May 17 (Reuters) - Japan's Nikkei stock average inched higher on Tuesday after a roller coaster morning session, as optimism about COVID-19 lockdowns ending in major trade partner China was countered by the drag from some disappointing financial results.

The Nikkei started about flat and then dipped into negative territory, only to rally with other regional markets after Chinese equities opened higher. However those gains fizzled into the midday break, with the benchmark ending just 0.2% up at 26,601.03.

Energy shares led gains among sub-indexes on the Nikkei, jumping 3.65% after crude oil rallied overnight on expectations for a recovery in Chinese demand.

The broader Topix added 0.14% to 1,865.88.

Shanghai aims to reopen broadly and allow normal life to resume for the city's 25 million people from June 1 following a painful, six-week COVID-19 lockdown.

Uniqlo store owner Fast Retailing, which has many Chinese outlets, was the Nikkei's biggest gainer by index points, up 0.67%.

Department store operator Isetan Mitsukoshi Holdings climbed 4.87%.

Oil company Inpex jumped 4.89%, making it the second-biggest mover in percentage terms, after shipper Kawasaki Kisen, which gained 5.3%.

The biggest decliner by a long margin was brewer Asahi Holdings, which tumbled 12.46% - shaving 20.5 index points from the Nikkei - after reporting an 83% drop in quarterly operating profit. Rival Kirin Holdings fell 3.25%.

Advertising giant Dentsu Group also sank on disappointing financial results, dropping 6.38%. (Editing by Rashmi Aich)