You're right, sick_em, the sheer audacity of this effort is astounding. I have immense respect for anyone who can go more than 200 k's in a day, and to more than double that is just... plain... superhuman.
There's no doubt in my mind that Kato did that distance, and there's also no doubt that it is an incredible achievement.
However this track has thrown up an interesting conundrum, in that no-one to my knowledge has ever sailed past midnight and kept going

... So we have two options:
Option 1) Allow people to pick and choose which 24 hour period they want to sail in. My problem with this is that someone could easily sail 100 km from midday till sunset, then have a nice meal, a sleep, wake up early the next morning and sail another 100 k's, for a total of 200 km in one 24 hour period. This isn't nearly as muscle-wrenching as a solid 200km in one session, and I really don't want to encourage this sort of manipulation. Apart from anything else, do you say that the session happened on the date that you started, or the date that you finished?
Option 2) Set the cutoff at midnight local time. This has the benefit of being clear, concise, there's no argument about which day you choose to take it as, and most GPS programs are set up to split files by date anyway.
I think we have to choose option 2) here, just from a parity / rulekeeping / keep it simple viewpoint.
It's worth remembering that although the GPS Team Challenge works well as a log of your sessions, it is first and foremost a competition, and we only have 6 categories to record performance in.
This has worked well for most things, however every now and again someone throws us a curve ball which shows that our system isn't perfect.
I would dearly love to record this amazing effort somehow, please remember that splitting the file by midnight doesn't mean that Kato hasn't done that distance, it just means that we don't have a way to record it!
If GPS-SS allows posting of any 24 hour period, then I would recommend posting the track on there, and making a link on your GTC session to the GPS-SS page.
On a personal note Kato, you are un... be... lievable!!!! I can't express just how amazing that effort is.