Race Recap: The 21st Hadano Tanzawa Minase River Half Marathon

On December 7, I ran the 21st Hadano Tamazawa Minase River Half Marathon. I finished in 1:49:43 (Gross) / 1:49:11 (Net). The time is about five minutes slower than last year, almost nine minutes slower than two years ago, and roughly eleven minutes off my course PR from 2017. Still, I feel good about the race because I stuck to my plan.

My goal was simple:

1. Take the first 5 km conservatively, and

2. Avoid pushing too hard on the early descent.

I managed both, and as a result I was able to pick up the pace from the 19 km mark and finish strong—exactly how I wanted.

Splits

0–1K: 5:38 (+0:22)
1–3K: 10:19 (5:09.30/K)
3–7K: 20:06 (5:00.15/K)
7–8K: 4:59
8–9K: 5:25
9–10K: 5:22
10–11K: 5:12
11–12K: 5:18
12–13K: 6:02
13–14K: 5:56
14–15K: 5:10
15–16K: 4:47
16–17K: 4:59
17–18K: 4:52
18–19K: 4:54
19–20K: 4:44
20–21K: 4:59
21–21.1K: 0:52
Total: 1:49:43 (Gross) / 1:49:11 (Net)

The major slowdown in the middle reflects the steep climb in the hilliest part of the course. Quite a few runners were walking there—something I was too proud to do. Ironically, one woman who was walking ended up passing me in the final kilometers. In hindsight, her strategy might have been smarter!

Conditions & Scenery

The weather was perfect for a half marathon: around 9°C at the start, little wind, and clear skies. The views were stunning, especially the mountainous section where Mt. Fuji appeared in the distance. It felt like a reward in the middle of the effort.

Gear & Reflections

I wore MUTEKI minimalist split-toe shoes, choosing minimal sole protection rather than going barefoot. I actually ran the race barefoot last year and finished in the 1:41 range—hard to believe now, considering it was my first Hadano race after a meniscus injury. The Hadano course is notoriously harsh on bare feet, with many rough or deliberately textured surfaces. This year, I wanted to test my cardio and leg strength, not my tolerance for pain.

Course Character

Compared with flat half marathons, Hadano is wonderfully varied: climbs, descents, turns, riverside paths, residential streets, pastoral stretches, and mountain views. Spectators were lively and supportive. Several elderly residents from care homes sat in chairs along the course, waving at runners. Some smiled back warmly when I waved—it was one of the emotional highlights of the day.

One thing I noticed this year is that we didn’t run the track before the finish, unlike last year. The organizers sometimes make small adjustments to the route, probably for traffic reasons. I’m not a huge fan of course changes, but that’s the reality of a city race.

Special Occasion & Guests

This year’s race doubled as a celebration of Hadano City’s 70th anniversary, and three guest runners joined the event. Standing next to me in the photo below (in black tights) is Nobuaki Murasawa, the 2017 Hokkaido Marathon champion. He kindly took a selfie with my friend and me.

Comedian Yoshio Kojima also appeared and ran the 5K. I didn’t realize he was such a star among kids, but the entertainment stage was full of excited boys copying his dance moves and having a great time. 

Final Thoughts

Compared with last year, I finished much less exhausted thanks to smarter pacing. That doesn’t mean I could have run faster—I genuinely gave everything I had. ChatGPT had suggested slightly quicker pacing in the steep section, but I simply didn’t have the strength. Those hills reminded me clearly of my weaknesses, but I’m not discouraged.

It’s not an ending—it’s the start of a new journey to become a stronger version of myself.