Nobu landed 4Ts and 4T-3T combinations back in the day – just not in the SP at Nationals, where he either popped or fell. For instance, at his last Nationals back in 2013 he popped his 4T in the short into a triple, but successfully completed a 4T-3T in his FS. This time it was sort of the other way round – he landed a gorgeous 4T-3T combination in his SP, but fell on an underrotated 4T in the FS.
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With that said, congratulations to Nobu, on showing the youngsters how it's done! His short was one of the highlights of the entire men's competition. It was so obvious that he simply enjoyed being there, entertaining his home audience, showing his family (who he said was in the audience) what he's still capable of and reaping the fruits of his hard work. Because hard work it must have been to get his jumps back to that level at 37 – just awesome!

Even with his fall on the 4T in the FS - his 4T-3T, his 3Axels and his other triples were as good as they had been back in the day, if not better! He says his knees and joints are done, but from the way he skated, you wouldn't know it.
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Regarding international assignments: Apart from the fact that he doesn't fulfil any of the previously published criteria for Worlds (for that he would have needed to medal) and only one for 4CC (top 10 at Nationals) (whereas those who were chosen fulfil multiple criteria), he had already hinted that he wishes to retire after these Nationals (source:
https://www.nikkansports.com/premium/sports/figure/news/202412210001328.html) and might have communicated this to the federation beforehand, so that he might not have been taken into consideration, even if he had been on the podium.