Like 'Geo' - that's been obvious for a while.

Lupinranger and Patoranger is selling well in the toys department, exceptionally and unprecedentedly so for the girl rangers. This is mostly due to the casting of Haruka Kudo, a former idol (Morning Musume), as Lupin Yellow. Toei and Bandai could be trying to repeat this success by having the next Rider being played by an idol or popular female personality as well.

From a creative standpoint, Toei might have just figured now, if any, is a good time to experiment. An anniversary series is a safe, low-risk playground for experimentation. People will watch the show regardless due to the return of legendary heroes, and the toys will sell for the same reason. At best, it could attract a new demographic to join the already existing one, at worst it would be a harmless try at something new (especially if the season is rumoured to be shorter than usual).

Zi-O is written "Ji-Ou" as in king of time or king of letters

Maybe Zi-O is a girl, but I really don't see anything particularly feminine about the costume or poses that other people are seeing. "The chest armour sort of looks like boobs" barely means anything since the other Rider has the same chest. Unless they're both girls?

The other rider's chest is markedly less pronounced from these images.

Zi-O's chest is... very, very odd. Like, even if it is larger to accommodate boobs, that chest plate is still extremely bizarre.

The Zi-O chest armor part doesn't looks feminine to me.....

Also Zi-O chest armor part looks very different with Femme armor.....

Zi-O chest armor part design are more suitable for male.....

This just upper armor and that's really similar to King Ranger, Ouja, and Mage.....

http://www.tokunation.com/attachment...1&d=1531359503

http://www.tokunation.com/attachment...1&d=1531359816

http://www.tokunation.com/attachment...1&d=1531359923

http://www.tokunation.com/attachment...1&d=1531360046

But if you look at it from other angles, it looks quite busty and feminine.

If we see from the top, yes the chest armor looks bigger but if we see in left side, the chest looks smaller and doesn't looks feminine :D

I honestly think that has more to do with the watch strap on the chest, because if you look at the black parts of the chest they're not as pronounced as the strap, and the fact the strap curves making the chest look more rounded. The secondary looks like has the same chest design as Zi-O, but it's just harder to tell because the black strap is not as pronounced as Zi-O's silver strap do to surrounding color choice.

I’m pretty skeptical too, as cool as I think it would be to have a girl Rider. I’m not getting my hopes up. Let’s just say I’ll be pleasantly surprised if it happens.

Regardless, there is definitely something weird going on with this Rider’s chest plate, judging strictly from these images, and it’s not just the added silver watch strap. It is freaking bulbous in the two “action pose” shots.

These are not your average toku chest armors...