Naoki (川島直輝) Kawashima

Ultrarunner since 2019

DUV-index ?Largest integer N such that the runner has at least N credited races of at least N km.

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

Countries visited ?

Japan

1,0%

Rank quotient ?This runner's calculation uses 7 eligible race(s): Σ(rank − 1) = 51; Σ finishers = 5 299. 51 / 5 299 × 100 = 0.96%. A win adds 0 to the numerator. Lower is better.

Totals

Ultras completed7

Km — ultra races671 km

> 100 km1

Longest race120,0 km

34th Fuji 5 Lakes Sparta Challenge — 21/4/2024

Km per year (ultra races)

100

2022

100

2023

120

2024

100

2025

2026

Race types (share of distance)

Road100,0%

Records

100 km7h16'43 50 mi6h17'36

HISTORY

7 race(s)

Date		Race	Perf.	Rk
2026
19.04	80km	36th Fuji 4 Lakes 80 km Challenge	6:17:36 h	5
2025
20.04	100km	35th Fuji 4 Lakes 100 km Challenge	7:36:50 h	4
2024
21.04	120km	34th Fuji 5 Lakes Sparta Challenge	11:51:58 h	15
2023
21.05	100km	11th Tokyo Shibamata 100 km	7:16:43 h	5
2022
17.04	100km	32th Fuji 5 Lakes 100 km Challenge	7:57:33 h	11
2019
07.10	100km	1st Fuji 4 Lakes 100 km Autumn Challenge	8:29:53 h	4
21.04	71km	29th Fuji 5 Lakes 71 km Challenge	6:16:01 h	14

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Runner	Races in common

DUV-index calculation details

#	Date	Race	Credited km	DUV-index+
✓ 1	21/4/2024	34th Fuji 5 Lakes Sparta Challenge	120,00	×4
✓ 2	20/4/2025	35th Fuji 4 Lakes 100 km Challenge	100,00	×4
✓ 3	21/5/2023	11th Tokyo Shibamata 100 km	100,00	×4
✓ 4	17/4/2022	32th Fuji 5 Lakes 100 km Challenge	100,00	×4
✓ 5	7/10/2019	1st Fuji 4 Lakes 100 km Autumn Challenge	100,00	×4
✓ 6	19/4/2026	36th Fuji 4 Lakes 80 km Challenge	80,00	×3
✓ 7	21/4/2019	29th Fuji 5 Lakes 71 km Challenge	71,00	×2