TOKYO: Japanese rubber futures closed at a near three-week low on Wednesday as concerns about surging coronavirus cases offset optimism over positive developments in vaccines to end the pandemic. Osaka Exchange's rubber contract for May delivery finished down 7.2 yen, or 3%, at 234.2 yen per kg, the lowest close since Nov. 20. The rubber contract on the Shanghai futures exchange for May delivery declined 4.1% to end the day at 14,260 yuan per tonne.