The two teams began their Group B campaigns with comfortable victories at the Chiayi City Baseball Field in Chiayi.

Japan were untroubled by Russia in the opening match of the eight team tournament, easing to an 15-0 win over their European rivals.

The US enjoyed the same margin of victory over Hong Kong, cruising to a 16-1 success.

The result leaves both teams at the top of the Group B standings after the opening day of a tournament being held for the first time in eight years. 

Second seeds South Korea battled to a 10-9 victory over the Czech Republic in the opening Group A match.

Hosts Chinese Taipei are due to play their first group match tomorrow when they take on South Korea.

Earlier in the day, the Czech Republic are scheduled to face Australia and Russia take on Hong Kong in Group B.

After a round-robin phase, the top two countries in each group will advance to the super round which will decide the two finalists.

The bottom two countries in the groups will enter the consolation round.

The tournament is due to conclude on July 15.

Tokyo hosted the last tournament staged in 2010, won by Cuba.

A planned edition for 2012 was then cancelled by the International University Sports Federation as organisers in Taoyuan, also in Taiwan, were unable to attract at least six teams to ensure the event could go ahead.

Twice champions Cuba are not taking part this year so there will be a different name on the trophy at the end of the sixth staging of the event.