Three team berths are up for grabs in both jumping and dressage at the European Championships in Rotterdam, with eventing spots being decided in Germany.
The battle to secure Olympic quota places in the equestrian sports steps up a gear in August, with some of the final sports up for grabs.
The jumping in the Netherlands is likely to be extremely competitive event with reigning Olympic gold medallists France, defending European champs Ireland, Great Britain, and Belgium among the countries seeking one of three spots in Japan next year.
At the end of the month is the FEI European Eventing Championships in Luhmuehlen, Germany (28 August to 1 September), which represents the penultimate opportunity for European eventing teams to qualify for the next Games.
Here are the things you need to know about the qualification process, the big names who could miss out, and the nations from other parts of the world who have already guaranteed their places at Tokyo 2020.
Germany's victory in last year's World Equestrian Games in Tryon, North Carolina ensured they would defend their Olympic team dressage title in Tokyo.
The top six from Tryon - Germany plus the United States, Great Britain, Sweden, the Netherlands and Spain - all qualified for the team competition next year alongside hosts Japan.
Australia's eighth place also saw them through to Tokyo as the top team from Olympic Group G covering Oceania and South East Asia.
In June, Russia joined them by winning the Group C (Eastern Europe and Central Asia) qualifier in Moscow.
The recent Pan American Games in Lima provided the next two teams in the form of winners Canada and bronze medallists Brazil, with runners-up USA having already qualified.
That leaves three spots from these European Championships - the top three teams who have not already qualified - plus the winner of the Group F (Africa and Middle East) qualifier to be held later this year.
Three rider and horse combinations from each team - a total of 45 - go into the individual competition at Tokyo 2020.
The remaining 15 spots, a maximum of one per country not in the team competition, will be decided by the FEI Olympic Athletes Rankings at the end of the year.
Germany, and West Germany pre-unification, have won almost every Olympic team dressage title since the boycott of the 1980 Moscow Games.
The one exception was London 2012 where Charlotte Dujardin inspired Great Britain to gold.
But in Isabell Werth, who made her Olympic debut as a 23-year-old at Barcelona 1992 before taking her only individual gold at Atlanta 1996, Germany have the biggest threat to Dujardin's hopes of a hat-trick of Olympic individual crowns.
Werth and her "dream horse" Bella Rose teamed up to win her fourth individual World Equestrian Games title in Tryon and the pair will be hard to stop in Tokyo next year.
Bella Rose recovered from serious injury with Werth deserting Weihegold, the horse on which she had won the previous two World Cup Finals, to be reunited with the mare.
Since then, Dujardin has established a new partnership with the mare Mount St John Freestyle and the pair took bronze behind Werth at last year's World Equestrian Games.
Splitting the pair in Tryon was Laura Graves and her mount Verdades.
The American took bronze at Rio 2016 behind Dujardin and Werth and has been second to the German at the last three World Cup Finals.
After the automatic spot for the hosts, the next six places in the Tokyo 2020 team jumping competition were also decided at the 2018 World Equestrian Games.
McLain Ward secured the United States a thrilling jump-off victory from Sweden with Germany taking bronze.
Switzerland, the Netherlands and Australia claimed the other qualification berths.
Reigning Olympic champions France were only ninth, with London 2012 gold medallists Great Britain just ahead of them.
They both have a final chance to qualify in Rotterdam, with defending European champions Ireland also under pressure after their seventh place in Tryon.
But these three nations will not have things their own way with Belgium, Italy, and Spain all capable of taking one of the three spots for Tokyo.
There are 20 countries in the Olympic team jumping competition with Israel and Ukraine emerging from the Group C competition in June.
Three nations came from the Pan American Games with Brazil taking victory from Mexico and the United States.
But with the Americans having already qualified, fourth-placed Canada took the third and final team spot from that event.
Marlon Zanotelli made it double gold for Brazil with two-time Olympian Jose María Larocca taking silver to secure an individual berth for Argentina at Tokyo 2020.
One rider from each of Colombia, Dominican Republic, and Chile will also be in the individual competition having missed out on the team event.
New Zealand and China took the two spots from the Group G qualification held in the Netherlands in August, which just leaves the three berths from the European Championships and two from October's Group F qualifier In Rabat, Morocco.
With three riders of each of the 20 teams and the four individual berths from the Pan American Games, the last 11 spots - one per country - will be decided by the FEI Olympic Athletes Rankings at the end of the year.
London 2012 champion Steve Guerdat is currently ranked number one in the world and, with Switzerland already qualified for Tokyo 2020, looks certain to be in the shake-up to regain his title.
The bronze medallist from last year's World Equestrian Games took his third World Cup Final in Gothenburg this year on board Alamo.
But he rides Bianca at the European Championships in Rotterdam.
When asked to compare his two current horses and Nino de Buissonets, the horse on which he won Olympic gold, he said of Alamo, "He's perhaps not the same genius as her (Bianca), but he is a real athlete and very powerful with a lot of blood. And there is no comparison with Nino!"
The Swiss are sure to be challenging for team gold with Tryon silver medallist Martin Fuchs also in their lineup.
Third in this year's World Cup Final was reigning European champion Peder Fredricson.
The Swede took silver at Rio 2016 and the European title on board All In, and the pair are reunited in the Netherlands as they bid to go one better in Tokyo.
But arguably the rider to beat is Simone Blum who took gold at last year's World Equestrian Games.
The 30-year-old has had a swift rise to the top after teaming up with the mare DSP Alice.
The duo won the German title in 2017 and then had five clear rounds to take a surprise victory in Tryon ahead of Swiss pair Fuchs and Guerdat.
Blum will be one of the favourites in Rotterdam this week and Tokyo next year.
But with those Olympic team places up for grabs, and talent spread throughout the field, the jumping promises to be the hottest contest of the week in Rotterdam.
As with dressage and jumping, the top six in the team eventing at the 2018 World Equestrian Games qualified for the Tokyo Games.
Victory went to Great Britain with Rosalind Canter, on just her second start for the national team, jumping a final clear to secure team and individual gold on board Allstar B.
Canter's heroics saw Britain pip Ireland with France taking bronze.
The other qualifiers were Germany, Australia, and New Zealand.
Poland won the Group C qualifier on home soil in May to join them and hosts Japan, with China and Thailand earning spots in Tokyo the same month in the Group F/G qualifier in France.
Having finished only eighth in the WEG, the United States secured their Olympic berth by winning the Pan American Games with Brazil taking the second spot.
Two teams will qualify from the European Eventing Championships in Luhmuehlen, Germany with one more coming from the FEI Eventing Nations Cup which ends in October.
As far as individual qualification for Tokyo 2020 is concerned, there are three riders from each qualified nation plus 20 from the FEI Olympic Athletes Rankings - one per country - at the end of the year to make a total of 65 entrants.
Michael Jung is seeking his fourth European title before bidding for a hat-trick of Olympic titles in Tokyo next year.
The 37-year-old retained his individual title at Rio 2016 and was part of the German team which took silver behind France as they just failed to land a third successive gold.
Jung rode Sam in both of his Olympic appearances, and his London 2012 triumph saw him become the first event rider to hold world, European and Olympic titles at the same time.
After Sam was retired after Rio, Jung has unsurprisingly struggled somewhat.
He and the mare fischerRocana FST enjoyed some success although he just failed in his bid for a fourth consecutive European Championship triumph - all on different horses - in Strzegom, Poland in 2017, finishing second behind fellow German Ingrid Klimke, the daughter of six-time Olympic gold medallist Reiner Klimke.
Lameness saw fischerRocana FST and Jung miss last year's World Equestrian Games, but he has now linked up with Chipmunk who was ridden by team-mate Julia Krajewski in Tryon.
Jung admits the new partnership is a work in progress but hopes he can challenge for gold again in Tokyo.
Reigning champ Klimke returns with her mount Hale Bob in a strong German squad on home soil.
Britain ended Germany's run of three consecutive European Championships wins in Poland two years ago, having won eight in a row from 1995 to 2007.
But it may not be a straight fight between the big two for gold in Luhmuehlen with Ireland in with a shout after their silver in Tryon and Olympic champions France also in the shake-up.
Tony Kennedy will make his international debut for Ireland after a late call-up, and rides Westeria Lane, a 14-year-old gelding who has one eye.
Kennedy, 25, told Horse and Hound his mount is "a phenomenal cross country horse" and says "he has always found jumping very easy".