The Japan Steel Works, Ltd.
5631.TMEDIUMSatellite · Weight: 10%· Data as of 2026-05-05
Investment Thesis
Sole Japanese manufacturer of large-caliber gun barrels (Type 19/99 howitzers, naval guns for Mogami-class FFM). Arms export reform April 21, 2026 — Japan scrapped 5-category restriction on lethal exports, opening Type 19 howitzer and Mogami naval gun barrel markets for the first time since WWII. JSW M&E subsidiary merged April 1, 2026 as Materials & Engineering Division — Muroran plant now unified production base. ATLA railgun program: JSW sole Japanese railgun developer, ship testing underway on JS Asuka (2022-2028 program). 1H FY2026: sales ¥135.7B (+25.3%), OP ¥12.2B (+47.1%). FY2026 guidance: rev ¥290B / OP ¥24.5B. Defense est. <15% of group revenue but policy tailwind accelerating. NOTE: PE CORRECTED — prior 17.3x was incorrect; actual PE 33-38x.
Risk
1) PE 33-38x vs machinery sector avg 12.3x — expensive for <15% defense revenue share. 2) Q3 FY2026 standalone OP -37% YoY, margin 8.1% vs 13.6% — stock -12.9% on Feb 17 miss. 3) FCF negative (op CF -¥4.6B FY2025). 4) Plastic injection molding (largest segment) exposed to CN slowdown. 5) New Muroran defense factory cancelled due to construction cost inflation.
Monitoring Trigger
May 13 FY2026 full-year (CORRECTED from May 8): verify OP ¥24.5B + operating CF status. Arms export: watch for Mogami-class or Type 19 export LOI. Railgun: ATLA trials 2027-2035. FY2027 MOD budget: Type 19/99 procurement units. If PE >40x without earnings catch-up, TRIM.
Key Dates
Update History
NEW ADDITION (Defense supply chain explore). Sole Japanese supplier of large-caliber gun barrels (Type 19/99 howitzer, naval guns). 1H FY2026 OP +47% YoY, FY2026e revenue ¥290B (+16.7%). PE 17.3x reasonable vs defense pure-plays.
Metrics corrected for cross-theme consistency with nuclear evolved entry. PE 17.3→34.6 (was tipranks error; fwd PE correct), PB 1.5→3.35, ROE 8.0%→9.2%, market_cap ¥718B→¥691B, div_yield 1.5%→0.96%, earnings date corrected to May 13.
PE CORRECTED 17.3→33.5x. Arms export reform Apr 21. JSW M&E merger Apr 1. Railgun on JS Asuka. Q3 OP -37% warning. Earnings date corrected May 8→May 13.
Key Metrics
Business Segments
| Segment | Revenue | Share | Description |
|---|---|---|---|
| Industrial Machinery Products | ¥175B (FY2026e) | 60% | Plastic injection molding machines, defense equipment (gun barrels, mortars), forging equipment |
| Material & Engineering Products | ¥115B (FY2026e) | 40% | Large steel castings/forgings (nuclear vessels, turbines), specialty steel, engineering services |
Supply Chain Evidence
| Evidence | Customer | Product | Detail |
|---|---|---|---|
| confirmed | JGSDF / ATLA | Type 19 155mm wheeled self-propelled howitzer (gun barrel + cannon) | JSW developed Type 19 leveraging Type 99 barrel lineage. Active deployment with 2nd Artillery Brigade since 2024. ~7 units/year procured.[source](2024-2026) |
| confirmed | JGSDF | Type 99 155mm self-propelled howitzer (barrel) | JSW is sole domestic supplier of large-caliber artillery barrels.[source](ongoing) |
| confirmed | JMSDF | Naval gun barrels (5" and below) | Historical naval gun manufacturer (Yamato 18.1" guns). Continues to supply naval gun forgings for FFM/Mogami class.[source](ongoing) |
| probable | ATLA / JMSDF (R&D) | Electromagnetic railgun program | Japan railgun development at ATLA — JSW is the natural domestic partner for barrel/launcher fabrication given large-bore barrel expertise.[source](2025+) |
| inferred | MHI / KHI (supply chain) | Specialty steel castings/forgings for naval and submarine programs | JSW historically supplies large-forging components to Japanese shipbuilders for naval programs. |
Sources & References
Peer Comparison
| Company | PE | Fwd PE | ROE | Op Margin | FCF |
|---|---|---|---|---|---|
| Mitsubishi Heavy Industries, Ltd. | 40.1 | 40.24 | 12.2% | 8.7% | +¥300B |
| ShinMaywa Industries, Ltd. | 16.5 | 18 | 8.18% | 4.5% | -¥11.0B |
| Tokyo Keiki | ~29.7 (actual FY2025 on ¥181 EPS; StockAnalysis shows 19.29x but uses stale FY2024 data) | 22.3 | ~7% (FY2025 actual; StockAnalysis 11.89% is stale FY2024) | ~4.6% (FY2025: OP ¥2.83B est. / Rev ¥61.5B) | N/A |
| ACSL Ltd. | N/A | N/A | -77.7% | -71% | -¥1.3B |
| The Japan Steel Works, Ltd. | 33.5 | 31.1 | 9.09% | 8.4% | -¥19.7B |
| SKY Perfect JSAT Holdings Inc. | 43.7 | 35 | 4.5% | 10% | +¥30B (est.) |
| Howa Machinery, Ltd. | 10.3 | 11 | 6.5% | 5.5% | +¥1B (est.) |