I do not recall doing a marathon in Guam.

I do remember running an event there, but it was more likely a 10K.

I also remember two other things while I was there:

1) I bought a nice Hawaiian-style shirt. The saleswoman in the hotel shop quided me to a more subdued one than my initial choice. I remember she said “you don’t want to go back to Japan looking like a Yakuza!”

2) I badly sunburned the tops of my feet while relaxing for a day or two after the race — the only area I forgot to slather with sunscreen. . .