Brett Larrner's recap of day 1 from the Hakone Ekiden is a must read. The times achieved were amazing. Yes the conditions were ideal as there was a slight tailwind, but the top 4 teams all broke the Day 1 record and 8 guys broke previous course records for their legs led by 19-year old Vincent Yegon who ran the 21.4 km third stage in 59:25. That's 58:35 half marathon pace and keep it going for nearly another minute. Pretty damn good for someone with 13:28/27:47 pbs.
After it was over, Larner tried to make sense of it all and he had no choice but to give a lot of the credit to the shoes.
What to make of it all?
Hakone legends doing guest commentary were stunned by the quality of the performances throughout the day. Yasuyuki Watanabe, former Hakone stage record holder and college coach of marathon national record holder Suguru Osako, said, "I kept thinking there was something wrong with my stopwatch. As someone who ran 66 minutes on the Second Stage I didn't think I'd see 65 minutes happen in my lifetime." Toshihiko Seko, another former Hakone record holder, one of the world's all-time great marathoners and current JAAF director of marathoning, could only stammer, "The conditions were really good."
He was right, of course, as temperatures were mostly under 10˚C and there was a very light tailwind much of the way, but the most honest commentary came from First Stage winner Yonemitsu. When an announcer asked him in a post-ran stage victory interview how it felt to have tied Watanabe's all-time #2 mark Yonemitsu answered, "Well, these days there are the shoes, the Vaporfly, so I don't feel especially psyched about it."
...19 of the 21 guys on the First Stage were wearing them [the Vaporflys]. The rest of the stages were probably about the same. If the shoes were banned tomorrow would today's marks ever be touched? Miyashita's Fifth Stage record, yes. The unbroken First Stage record, probably. Yoshida's Fourth Stage record, maybe. Aizawa's Second Stage record, probably not. Yegon's Third Stage record, no way in hell.
In terms of relation to the times and records of Hakone's past the elephant in the room is probably more of a bull in a china shop.