Seiya
Maikuma
RBJapan · AZ Alkmaar
Player dossierEredivisie
SeiyaMaikuma
RBRight-BackDefender
- Club
- AZ Alkmaar
- League
- Eredivisie
- Nationality
- Japan
- Age
- 28
- Height
- 179 cm
- Foot
- Right
- Valued
- 28 May 2026
EredivisieReading the valuation
The market values Maikuma at €2M. Model A, which never saw Maikuma during training, estimates €2.1M: the market value is 3% below that estimate.
That is a factor of ×1.03. Model A's typical held-out miss is ×1.50 either way, so this gap is within its usual error.
Without league and club, Model B estimates €5.1M, further from the market. Model B is usually further off (typical miss ×2.07): league and club explain much of how the market prices players.
A gap describes the model's arithmetic for this player's inputs, not what the player is worth.
- Apps
- 50
- Minutes
- 3,438
- Goals
- 2
- Assists
- 3
- Started
- 37/50
- Min / app
- 69
- Cards
- 3Y 0R
Club matches, two years to the valuation date
The Valuation Journey
What moves Model A
Asking the prediction API to explain Model A for Maikuma…
SHAP describes the model's arithmetic for this player's inputs, not what causes market value. Model B can be explained only by the live service; Model A also has a published explanation for the research players.
Model A vs Model B against the observed €2M
Checking APIAsking the prediction API…
Held-out estimates come from cross-validation, with this player outside the training data: the honest comparison. Served models were refitted on every player, this one included, so they sit closer to the market. Shaded band: Model A's typical miss (×1.50 either way).
Player traitspercentiles vs 2,065 defenders
Dashed ring: the defender median (50th percentile)
European club minutes
Share of minutes played in UEFA club competitions.
28% this player0% defender median93rd percentile
No passing, progression or defensive actions exist in the dataset, so no trait claims to measure them.
Valuation history every Transfermarkt valuation on record
- First valuation
- €300k
- Jan 2021
- Peak
- €4M
- May 2025
- Model target
- €2M
- May 2026
- Valuations
- 13
- 2 club changes
May 2026: €2M, AZ Alkmaar. Dotted lines mark the €2M, €10M and €30M tier boundaries.
Show as a table
| Date | Market value | Club |
|---|---|---|
| 2021-01-27 | €300k | V-Varen Nagasaki |
| 2021-06-28 | €450k | V-Varen Nagasaki |
| 2022-01-14 | €650k | Cerezo Osaka |
| 2022-06-28 | €750k | Cerezo Osaka |
| 2023-01-06 | €900k | Cerezo Osaka |
| 2023-06-28 | €1M | Cerezo Osaka |
| 2024-01-09 | €1.3M | Cerezo Osaka |
| 2024-06-12 | €1.5M | Cerezo Osaka |
| 2024-10-14 | €3M | AZ Alkmaar |
| 2024-12-17 | €3M | AZ Alkmaar |
| 2025-05-28 | €4M | AZ Alkmaar |
| 2025-12-02 | €3M | AZ Alkmaar |
| 2026-05-28 | €2M | AZ Alkmaar |
Audit context group-level, not about this player
- Audit group
- non-UEFA
- Population gap, Model A
- +0.093 95% CI +0.063 to +0.124
- This player, market vs held-out A
- −0.030
The group comes from first-listed citizenship and is never a model input. Across the population, non-UEFA players' market values sit about 10% above Model A's held-out estimates, relative to UEFA players in the same leagues. One player's residual says nothing about that pattern (typical miss ×1.50), and none of it is evidence of discrimination: the target may itself be biased. Open the Fairness Audit
In context observed value among comparable players in this build
All players in the Terminal →Eredivisie425 players · median €1M
Valued above 62% of the 425 Eredivisie players.
See them in the Explorer →Defenders, all leagues2,065 players · median €2M
Valued above 49% of the 2,065 defenders.
See them in the Explorer →Where Maikuma appears
Watchlists and the comparison tray are kept in this browser only.
Near this valuation closest observed values: same league, then same position
- BerghuisRWAjax Amsterdam · Eredivisie€2M
- KlaassenCMAjax Amsterdam · Eredivisie€2M
- OlijGKPSV Eindhoven · Eredivisie€2M
- WeghorstCFAjax Amsterdam · Eredivisie€2M
- HummelsCBAS Roma · defenders€2M
- GünterLBSC Freiburg · defenders€2M
- KohrCB1.FSV Mainz 05 · defenders€2M
- KayembeLBKRC Genk · defenders€2M
Counts and ranks of observed Transfermarkt values only; model errors are never ranked here. Full player export: Every player in the modelling population (D-011).