Ryosuke (斎藤良介) Saito
ID 566064
Born : 1985 Cat. M40 Ultrarunner since 2009 JPN
24
DUV-index ?Largest integer N such that the runner has at least N credited races of at least N km.
50
DUV-index+ ?Largest integer N such that the race distances provide at least N complete segments of N km in total. A single long race may therefore contribute several segments. See the DUV-Index tab for the detailed calculation. calculation details
1
Countries visited ?JPNJapan
1,2%
Rank quotient ?This runner's calculation uses 24 eligible race(s): Σ(rank − 1) = 198; Σ finishers = 16 916. 198 / 16 916 × 100 = 1.17%. A win adds 0 to the numerator. Lower is better.

Totals

Ultras completed24
Km — ultra races2 731 km
> 100 km7
> 160 km3
> 200 km3
> 24h3
Longest race231,3 km
IAU 24h Asia and Oceania Championships Open — 23/5/2026

Km per year (ultra races)

100
1 race
2022
218
2 races
2023
200
2 races
2024
440
3 races
2025
548
3 races
2026

Race types (share of distance)

Road98,3%
Trail1,7%

Wins & podiums (ultra)

🏆 Win1
🏆 Win M1
🏅 Top 37
🏅 Top 3 M7
Longest winning streak1
Current streak0

Records

50 km3h26'17100 km7h28'2924 h231,25 km

HISTORY

24 race(s) · 1 split(s) nested
DateRacePerf.Rk
2026
14.06 100km JPN20th Iwate Ginga 100km Marathon Challenge 8:16:03 h12
23.05 24h JPNIAU 24h Asia and Oceania Championships Open 231.250 km4
28.03 24h JPN17th Jingu Gaien 24 Hour Challenge 216.331 km9
2025
29.06 100km JPN40. Lake Saroma 100 km Ultramarathon 7:50:14 h26
24.05 24h JPN4th Hirosaki 24h Ultra Run 219.778 km10
20.04 120km JPN35th Fuji 5 Lakes Sparta Challenge 9:44:44 h5
2024
09.06 100km JPN18th Iwate Ginga 100km Marathon Challenge 7:51:03 h2 🥈
19.05 100km JPN30th Yatsugatake Nobeyama 100 km 8:23:15 h4
2023
11.06 100km JPN17th Iwate Ginga 100km Marathon Challenge 8:01:32 h6
16.04 118km JPN33th Fuji 5 Lakes 118 km Challenge 10:06:42 h8
2022
12.06 100km JPN16th Iwate Ginga 100km Marathon Challenge 8:18:32 h15
2019
20.10 100km JPN8th Noto Peninsula 100 km Ultra Marathon 8:04:26 h2 🥈
09.06 100km JPN15th Iwate Ginga 100km Marathon Challenge 7:46:55 h5
11.05 50km JPN1st Izu Oshima Geopark Ultra Marathon 3:26:17 h2 🥈
2018
10.06 100km JPN7th Hida Takayama 100 km Ultramarathon 8:08:12 h3 🥉
2017
25.06 100km JPN32. Lake Saroma 100 km Ultramarathon 7:28:29 h18
23.04 118km JPN27th Fuji 5 Lakes 118 km Challenge 9:42:15 h7
2016
12.06 45.4km JPN9th Skyline Trail Sugadaira 4:56:57 h17
27.03 100km JPN12th Izu Oshima Ultra 100 km 7:47:31 h2 🥈
2015
18.10 100km JPN21st River Shimanto 100km 8:13:30 h14
28.03 100km JPN11th Izu Oshima Ultra 100 km 8:13:21 h2 🥈
2014
29.06 100km JPN29. Lake Saroma 100 km Ultramarathon 7:56:24 h30
29.03 100km JPN10th Izu Oshima Ultra 100 km 7:53:24 h1 🏆
2009
26.04 112km JPN19th Fuji 5 Lakes 112 km Challenge 10:35:01 h18