The 200 freestyle is half the distance of a 400 free, yet light years apart.

Though the strokes are the same, comparing the two events is like comparing Nathan Adrian to Connor Jaeger. They are very different: The 400, for example, is considered “distance” and requires a distance training regime, a distance foundation, and a distance fanatic’s enthusiasm (think: Erik Vendt). The 200, on the other hand, is a “long sprint” that requires equal amounts of pacing and sprinting. 200 freestylers must be sprint-oriented enough to display speed, but distance-oriented enough to hang on.

Easier said than done.

A 200 free is often a melting pot of sprinters and distance veterans. One-hundred freestylers “upgrade” and try their luck at a 200, flying and dying. On the other hand, 400 freestylers “downsize” and give the 200 a whirl, attempting to move arms as fast as possible, like a freight train.

The defending Olympic champion in the 200 free, Katie Ledecky, is so unique and so rare a swimmer because she’s a distance swimmer who can sprint. There aren’t many distance swimmers who can excel at a 200 free, let alone also swim in an Olympic 400 freestyle relay. Ledecky has done both.

At this week’s Phillips 66 National Championships in Irvine, California, Ledecky takes one more step to assert her dominance in the 200. Naturally, a slew of other 200 freestylers will try to usurp her 200 freestyle throne. Is it possible? Can it be done? Could anyone in this field this week upset one of the greatest swimmers our sport has seen? While there are many 200 freestyle racing strategies, there are an equal number of reasons why the women’s 200 free is this week’s Can’t Miss Race.

For starters, Katie Ledecky should be reason enough to watch this race. A once-in-a-generation athlete. A phenom. We’ve simply run out of adjectives to describe Ledecky, an athlete who has astounded fans, coaches, teammates and competitors.

Katie Ledecky makes any race a Can’t Miss Race.

However, also watch for what could be an exciting battle for second, third, and fourth place. It’s a race that could come down to the final meter, one that will solidify the Pan Pacific Championships 800 freestyle relay roster. A number of swimmers hope to do just that.

Swimmers like Missy Franklin. Franklin aims to return to gold-medal-winning form after missing the championship finals in her 2016 Olympic individual events. A top-four podium spot would be huge momentum for Franklin. But she’ll have her hands full with swimmers like Leah Smith — who may be the nation’s best overall freestyler not named Katie Ledecky — as well as Melanie Margalis, Mallory Comerford, sprint extraordinaire Simone Manuel, and 2012 Olympic gold medalist in this event, Allison Schmitt.

In some ways, these events where the top four swimmers (or top six, including alternate relay selections) advance to international roster squads are the most exciting events to watch. These events often include several swimmers’ only or last chance to make an international roster spot. I remember watching previous Olympic Trials’ 200 freestyles, crossing my fingers that a certain name would earn 6th place and qualify for a long sought-after Olympic roster spot. Whereas the top two podium places often go to swimming heavyweights (think: Michael Phelps), the final relay spots often go to those swimmers on the periphery of always-qualifying but who haven’t yet broken through. Those swimmers are equally fun to root on.

Don’t miss this week’s women’s 200 freestyle. It’s an event that has it all: A swimmer who may break a world record, a swimmer trying to do whatever possible to make a once-in-a-life upset, a few Olympic gold medalist veterans attempting to return to form, and hungry swimmers aiming to punch a ticket to Tokyo and this summer’s Pan Pacific Championships.

It’s an event with a melting pot of swimmers. An event that may come down to the last few strokes. Some will sprint and charge towards the wall. Others will hope to hang on.

As for who wins? Only time will tell.