Naomi Osaka, Ozeki

Naomi Osaka became the 41st female Ozeki (=Champion) of the open era today by reaching the quarterfinals of the 2019 Australian Open, which follows on her maiden grand slam victory at the 2018 US Open (the Ozeki list will be updated once the tournament has been completed). Osaka could even make it to Yokozuna (=Grand Champion) if she wins the tournament. Moving from nowhere to Yokozuna within two slams would be a first in open era history. Osaka is also the first Japanese to reach Ozeki rank, in either the men's or the women's game.
 
Elsewhere, Dai-Yokozuna (=Great Grand Champion) Roger Federer lost active status after losing in the round of 16. Inactive Yokozuna Andy Murray lost in the first round and may retire. If it comes to this, we will pay our dues with an extra article on this page.

Further, the Australian Open turn out to be an Ozeki massacre, with Marin Cilic, Sloane Stephens, Madison Keys and Angelique Kerber all going out before the quarterfinals. Cilic, Stephens, Keys, and Juan Martin del Potro - who missed the Australian Open injured - go kadoban (they need to reach the quarterfinals at the 2019 French Open to defend the rank). Kerber was already kadoban and hence gets demoted to Sekiwake (=Junior Champion I) after the tournament.

Dai-Yokozuna Serena Williams, by contrast, reached the quarter-finals after a thriller against ex-Ozeki Simona Halep, and remains on-track to win her 24th grand slam title - which would have her take first place from Margaret Court in our open era ranking.