What a difference a year can make!

Last year at this time, the circuit was dominated by distinct players/pairs: Kento Momota (men’s singles), Tai Tzu Ying (women’s singles), Marcus Fernaldi Gideon/Kevin Sanjaya Sukamuljo (men’s doubles), Japan in women’s doubles, and Zheng Si Wei/Huang Ya Qiong (mixed doubles).

A year later, while these players are still formidable contenders, there is no sense of infallibility in four of the five categories. The only exception, of course, is Zheng/Huang, who have rarely let their foot off the pedal. The reigning world champions are heavily favoured to retain their crown in Basel.

What makes Zheng/Huang exceptional is that they have never lost twice to the same pair. The most high-profile of these losses was to compatriots Wang Yi Lyu/Huang Dong Ping at the HSBC BWF World Tour Finals – which was avenged at the Malaysia Open this year.

Any pair that hopes to claim the world title in Basel will probably have to get past Zheng/Huang. Those who have beaten them once – Wang/Huang, Thailand’s Dechapol Puavaranukroh/Sapsiree Taerattanachai, Japan’s Yuta Watanabe/Arisa Higashino, Malaysia’s Chan Peng Soon/Goh Liu Ying – are all serious contenders at the Worlds, but all will know that it will take a monumental effort to upset the world’s best pair.

The other categories are far more open.

Kento Momota is still the player to beat in men’s singles, but the aura that he carried in Nanjing has dissipated. The player most responsible for that was China’s Shi Yuqi, who twice thwarted the Japanese in high-stakes battles – in Guangzhou last year, and in the Sudirman Cup final this year. Shi unluckily suffered an ankle injury at the Indonesia Open and had to subsequently call off his participation for the World Championships.

Other strong contenders are Indonesia’s Anthony Sinisuka Ginting and Jonatan Christie; Indonesia Open winner Chou Tien Chen and Denmark’s Anders Antonsen. Veterans Lin Dan and Chen Long will also be in the reckoning. Lin Dan, given his surprise win at the Malaysia Open, will back himself for his sixth world title – a monumental achievement should it come to pass. Meanwhile, Denmark will bank on Anders Antonsen as Viktor Axelsen was sidelined with a back problem.

In women’s singles, Tai Tzu Ying will hope to break her World Championships jinx. Last year she was shocked in the quarterfinals; this year her performances in the run-up to the Worlds haven’t been of her usual lofty standard, and it will be interesting to see if she can raise the bar in Basel.

The players most in focus will be Chen Yu Fei, the All England champion who has won four tournaments this season besides leading China to the Sudirman Cup title, and Japan’s Akane Yamaguchi, who won back-to-back titles in Indonesia and Japan.

Women’s singles has a recent tradition of being the most competitive of all categories, and their challengers will be many, including the likes of India’s Pusarla V Sindhu and Saina Nehwal, Japan’s Nozomi Okuhara and Thailand’s Ratchanok Intanon.

Spain’s Carolina Marin, winner of a record three titles, will miss Basel as she could not recover in time after suffering a knee injury in January.

In men’s doubles, Gideon and Sukamuljo regained their glow which they had lost early this season. The Minions salvaged what was an average season with victories in Indonesia and Japan, and will hope things go their way as they seek their first world crown. Their chief challengers are China’s Li Jun Hui/Liu Yu Chen; Japan’s Takeshi Kamura/Keigo Sonoda and Hiroyuki Endo/Yuta Watanabe; Indonesian compatriots Mohammad Ahsan/Hendra Setiawan and Fajar Alfian/Muhammad Rian Ardianto, and Denmark’s Kim Astrup/Anders Skaarup Rasmussen.

Japan have the aces in women’s doubles, with the three highest ranked pairs led by reigning champions Mayu Matsumoto/Wakana Nagahara. However, Japan are not the unstoppable force they were not so long ago. The revival of fortunes of China’s Chen Qing Chen/Jia Yi Fan – who won the All England, the Malaysia Open and the Badminton Asia Championships this year – has opened the field, as has the form of Du Yue/Li Yin Hui, who beat two of the top Japanese pairs on their way to the German Open title.

Kim So Yeong and Kong Hee Yong were brilliant in Japan and will be reckoned as top contenders. Other pairs, such as Indonesia’s Greysia Polii/Apriyani Rahayu, Bulgaria’s Stoeva sisters, and Korea’s Lee So Hee/Shin Seung Chan have the ability to go far in the draw.