Racing at the Sailing World Championships is due to begin tomorrow ©World Sailing

A major test along the road to the Tokyo 2020 Olympic Games will begin tomorrow when the fifth Sailing World Championships gets underway in the Bay of Aarhus.

Racing will take place across all 10 categories due to be contested in the Japanese capital over 11 days of competition.

The event, which includes Olympic qualifying opportunities, is only held once every four years.

Almost 100 nations will be represented in Danish waters.

Competition will begin with racing in the finn class and the men's and women's 470 divisions tomorrow.

Olympic silver and bronze medallists Matthew Belcher and William Ryan of Australia and Panagiotis Mantis and Pavlos Kagialis of Greece will lock horns with in-form Swedes Anton Dahlberg and Fredrik Bergström, the reigning European champions, in the men's 470.

Slovenia's world number one ranked Tina Mrak and Veronika Macarol will face competition from the likes of Great Britain's Hannah Mills and Eilidh McIntyre in the women's 470.

Edward Wright will lead the British Finn charge in the absence of Olympic champion Giles Scott, who has opted to focus on training for the first Tokyo 2020 test event in September.

United States' Olympic bronze medallist Caleb Paine, Brazil's Jorge Zarif and The Netherlands' Pieter-Jan Postma are other leading contenders.

French trio Louis Giard, Pierre Le Coq and Thomas Goyard will start as favourites in the men's windsurfing R:SX class after consistently good World Cup performances.

Double Olympic champion Dutchman Dorian Van Rijsselberghe will chase a sixth World Championship medal, and second gold, while China's Bing Ye will start as defending champion. 

Defending champion and Rio 2016 Olympic silver medallist Peina Chen and bronze medallist Yunxiu Lu will lead a strong Chinese team in the corresponding women's event. 

The fleet will also include Olympic gold medallists from London 2012 and Rio 2016 in Spain's Marina Alabau and France's Charline Picon, who has returned from time out for the birth of her first child this year.

Australia's Tom Burton leads a strong laser fleet also featuring New Zealand's Sam Meech, Germany's Phiipp Buhl and Britain's Nick Thompson.

Reigning world and Olympic champion Marit Bouwmeester will seek to add to her impressive array of titles in the laser radial division.

The Dutchwoman, who was named 2017 Rolex World Sailor of the Year, will face competition from rivals including Denmark's home hope Anne-Marie Rindom, Belgium's Emma Plasschaert and Hungary's Mária Érdi.