Yu Zidi, the Chinese 12-year-old who will race in the final of the 200m medley this evening here at the World swimming championships in Singapore, is eligible to compete but cannot break World junior records, it seems.

Yu is the fastest 12-year-old in swimming history, her times in the 200m butterfly and both medleys, over 200 and 400m, are not only good enough to make senior finals here at swimming's global senior showcase but could get the pre-teen on the podium.

There's inconsistency in the rule book, however, and while Yu can race and even win medals among those 14 years or older, she s not eligible to hold a Wold Junior record.

Among questions being asked by media: if she's not senior, nor junior, then does swimming now have a new Kindergarten class?

Who's Yu? ...

Who’s Yu? We Take A Look As Zidi, 12, Swiftest Pre-Teen In History, Makes China’s World-Titles Team

As Yu Zidi, the 12-year-old swim sensation, heads into the 400m medley on the last day at Chinese Championships, we take a look at just how off-the-chart her speed is for one so young

State Of Swimming +Craig Lord

Here's the background on a debate that dates back to 1991 and another Chinese 12-year-old, whose victory at World Championships sparked the introduction of a lower age limit of 14.