Kosei Suwama

Season	Club	Apps	Match	RTG	Season
2026/27	Yokohama F. Marinos	7	6.81	—	—
2024/25	Yokohama F. Marinos	1	6.3	—	—
2024/25	Tsukuba University	1	—	—	—
2022/23	Tsukuba University	1	—	—	—

Domestic-league totals per season. RTG = Field Insider Rating (potential / ceiling); Season = age-blind form that year.

Japan · international

Side	Apps	G
Japan U20	1	0

Career caps & goals — tournament breakdown in the full career.

Scout report

Squad depthCentral defender

K. Suwama is a 23-year-old central defender at Yokohama F. Marinos, rated 43.5 overall by Field Insider's model, ranking 94th of 379 on scout potential in the J1 League. An emerging talent, he has been a fringe squad member this season (23.9% of available minutes). His defensive output reads 3.06 tackles, blocks and interceptions per 90. Below: strengths, watch-points, market-value outlook and the latest transfer news on Suwama.

Judged on this season alone, Suwama graded 4 — a workmanlike campaign that ranks 75th of 76 of the 76 centre-backs in the J1 League, on 0 clean sheets and 3.057 defensive actions per 90.

We hold a single season for Suwama, so there's no year-on-year comparison to draw yet — the read above is this campaign only.

On long-term talent our Rating reads 44, top 28% of the 76 centre-backs in the J1 League. At 23 Suwama is still climbing toward his ceiling, and a market index of 11.9 reflects that trajectory.

Current potential21st of 76 centre-backs · J1 League · 0 apps Current season75th of 76 centre-backs · J1 League · 0 apps75th-best centre-back in the J1 League94th in the J1 League · potential21st-highest potential centre-back in the J1 League

43.5

Ratingi

21st of 76 centre-backs

3.9

Seasoni

below regular-starter level

23.9%

Minutes

limited game time

3.06

Def. actions / 90

moderate defensive volume

Output in context · Yokohama F. Marinos finished 15th of 20 · a lower-table side

Apps

Goals

Assists

Clean sheets

No league appearances recorded this season, so there's no output sample to read yet.

Watch points

Game time. Only 23.9% of available minutes — needs a settled run to prove the level.
Level. Rates below a nailed-on top-tier starter on our model.

Outlook

With a Rating of 43.5, Suwama carries the 21st-highest potential of the centre-backs in the J1 League of 76 — though on just 0 appearances this season, so the standing rests on a small sample. Defensively he reads as moderate defensive volume (3.06 tackles, blocks & interceptions per 90). Approaching peak years; value is still building (price multiplier 2×) with the best seasons likely ahead.

Generated from Field Insider's rating model · AI-written analysis to follow.

Per 90 & availability

Minutes played %23.9%

Available fixtures37 of 38

Goals / 900

Assists / 900

Goal contribution / 900

Defensive actions / 903.057

Player flow

Goal involvements0

Cards / 900.113

Value & potential by age

Market valueRating

Solid = now · dashed = projected

The gold line is market value — an index (not €) blending rating, age and league. It climbs through the early 20s, peaks around ages 23–27 (~12), then tapers with age. At 23, Suwama sits on 11.9, at or near its peak. The blue line is Suwama's projected Rating — 43.5 today — recomputed at each age, so it follows the same rise-and-fall as a career matures and declines. Solid = up to today; dashed = projected.

Season statistics

Bars = where he ranks among centre-backs in the J1 League with 600+ minutes this season.

Shooting

Goals0

Passing

Assists0

Defending

Tackles8

Interceptions8

Blocks11

Yellow/red cards

Yellow cards1

Red cards0

Transfer history

Yokohama F. Marinos2024/25 – nowFree

Tsukuba Univ.until 2024/25

Yokohama F. Marinos2024/25 – 2024/25

Tomori Beratuntil 2024/25

Tsukuba University(back from loan)2024/25 – 2024/25

Yokohama F. Marinos2024/25 – 2024/25Free

Yokohama F. Marinos(on loan)2023/24 – 2024/25

Tsukuba Universityuntil 2023/24

About K. Suwama

Kosei Suwama is a 23-year-old centre-back who plays for Yokohama F. Marinos, born on June 6, 2003, standing 186 cm tall. He is from Japan. Yokohama F. Marinos currently sit 15th of 20 in the J1 League.

When K. Suwama plays, Yokohama F. Marinos's record this season is 1W-2D-9L — and his match ratings average 7 at home against 6.84 on the road.

Recent matches

September 23, 2025: 1-3 loss away at Gamba Osaka (90 minutes, 6.7 rating)
September 20, 2025: 2-0 win at home vs Avispa Fukuoka (9 minutes, 6.9 rating)
August 30, 2025: 0-1 loss away at Vissel Kobe (45 minutes, 6.6 rating)
May 17, 2025: 0-3 loss at home vs Kyoto Sanga (10 minutes, 6.9 rating)
May 14, 2025: 0-2 loss at home vs Kashiwa Reysol (90 minutes, 7.2 rating)
May 11, 2025: 0-1 loss away at Cerezo Osaka (90 minutes, 7.2 rating)
April 20, 2025: 1-3 loss away at Urawa (90 minutes, 6.2 rating)
April 16, 2025: 2-3 loss at home vs Shimizu S-pulse (90 minutes, 6.7 rating)
April 12, 2025: 1-2 loss away at Avispa Fukuoka (90 minutes, 7.3 rating)
April 9, 2025: 3-3 draw away at Kawasaki Frontale (90 minutes, 7.2 rating)

Field Insider's view

Field Insider currently rates K. Suwama at 43.5 with a Season form score of 3.9, ranking 94th of 379 centre-backs in the J1 League. See the full scout report for strengths, watch-points and the market-value outlook.

Career

Across 3 recorded seasons, K. Suwama has totalled 10 club appearances with 0 goals and 0 assists for 2 different clubs. His busiest campaign came in 2026/27, with 7 appearances for Yokohama F. Marinos.

K. Suwama's career has also included time at Tsukuba Univ., Tomori Berat and Tsukuba University.

On the international stage, K. Suwama has represented Japan U20 — 1 cap in our records.

Transfer news

No transfer news found for this player.