Okinawa City Marathon Numbers

Official time: 3:28.59
Chip time: 3:28.45
Watch time: 3:28.57

Chip time at half: 1:39.28
Watch time at half: 1:39.28

Heart rate average: 169bpm (beats per minute)
Heart rate range: 148-184bpm
Time spent above 170bpm: 1 hour, 45 minutes
Time spent below 150bpm: 2 minutes, 20 seconds

Ascent: 1030' (~340m)
Descent: 960' (~315m) (changing barometric pressure explains the discrepancy)
High: 430' (~140m)
Low: 30' (~10m)

5k time breakdown
0-5k: 23.23
5-10k: 23.06
10-15k: 24.23.7
15-20k: 23.13.7
20-25k: 25.01.1
25-30k: 25.30.3
30-35k: 25.38.9
35-40k: 26.39
the last 5k (37.195-42.195k): 25.33

10k time breakdown
0-10k: 46.29
10-20k: 47.37
20-30k: 50.32
30-40k: 52.18

Half breakdown
1st half: 1:39.28
2nd half: 1: 49.31

Heart rate breakdown(cumulative average)
5k: 155bpm
10k: 160
15k: 162
20k: 164
25k: 166
30k: 167
35k: 167
40k: 169
42.195k: 169
heart rate as I crossed the finish line: 184

I think the 5k time breakdown is the best statistic. It's easy to see that a significant hill was encountered between 10k and 15k. Also, the majority of the hills come between 25k and 35k. 35k to the finish is just fatigue. If you look at the 37.195k to finish 5k time and work backwards, you'll see that I cost myself over a minute on the 35-37k section.

I spent more time than usual watching my heart rate during this race. I knew that although I was speedy during the first half, I wasn't overexerting because much of my time was spent below 160. Anything in the 150's during a marathon is really sustainable for me. I was even spending some time in the 150's after 20k, which was encouraging.