Startup
KFKyoto Fusioneering
京都フュージョニアリング株式会社
#10 in the Japan Top 100 Startups
| Founded / HQ | 2019 · Tokyo / Kyoto |
|---|---|
| Equity raised to date | ¥32.98B “累計エクイティ調達額は329.8億円” Company-stated cumulative · as of 24 Aug 2026 · Kyoto Fusioneering Equity only; the Series D package also included ¥9.0B of credit/loan facilities. |
| Last round | 24 Aug 2026 · Series D (first close) · ¥16.72B エクイティ167.2億円（総額257.2億円） |
| Latest public valuation | Not publicly disclosed (we do not estimate) |
| Key investors | IMM Investment Japan, SiteGround Capital, GX Acceleration Agency, Development Bank of Japan |
| Unicorn | No |
| Website | kyotofusioneering.com |
From Japanese sources
Findings from Japanese-language filings, government records, trade press, interviews and job posts, with our English analysis. Items tagged Japanese-only had no English coverage when we checked quickly. Most insightful first.
| 2026-09-14 | GovernmentJapanese-onlyConditionally selected for METI's fusion power-generation demonstration subsidy 経済産業省「令和７年度補正フュージョンエネルギー発電実証推進事業補助金」において、条件付き採択事業者に選出 A consortium led by spin-off Starlight Engine was conditionally selected to demonstrate power generation with a high-temperature-superconducting tokamak. This is METI's first fusion power-demo subsidy, and it effectively names Starlight Engine as a national champion candidate. Final award terms are still pending. Source: Kyoto Fusioneering (JP release) |
|---|---|
| 2025-12-23 | Regulatory filingJapanese-onlyKyoto Fusioneering's FY9/2025 notice: net loss ¥2.48B, ¥12.8B current assets 京都フュージョニアリング 第7期決算公告 The balance sheet as of 30 Sep 2025 shows total assets of ¥15.2B, mostly current (¥12.8B, largely cash), an accumulated deficit of ¥6.17B, and a ¥2.48B net loss for the year. That is plenty of runway before the ¥25.7B Series D close, so the Series D funds expansion rather than survival. Source: gBizINFO (METI) public notice |
Overview
Kyoto Fusioneering develops and engineers plant equipment and systems for fusion power, such as gyrotrons, divertors and breeding blankets, and supplies them to fusion projects. It runs test facilities including UNITY-1 in Kyoto and is building UNITY-3, a breeding-blanket test facility, with Oak Ridge National Laboratory in the US, and works with General Atomics on divertor development. It earns from equipment and engineering contracts and government programmes such as METI’s fusion demonstration subsidy. Equity raised through the Series C extension totals about ¥16.26B.
Built from: Newsroom · Series C close release
Company timeline
Founded
| Date | 2019-10· Kyoto Fusioneering |
|---|---|
| Founders | Satoshi Konishi, Taka Nagao |
Funding
| Date | Round | Amount | Lead / key investors | Source |
|---|---|---|---|---|
| 2021-01-20 | Funding (close) | ¥120M 総額1.2億円 | PR TIMES | |
| 2022-02-02 | Funding | ¥2B 総額20億円 | PR TIMES | |
| 2022-03-07 | Debt | ¥100M 総額1億円 | PR TIMES | |
| 2022-04-12 | Debt | ¥150M 1億5,000万円 | PR TIMES | |
| 2023-05-17 | Series C | ¥10.5B (cumulative ¥12.2B) シリーズCで総額105億円 | Kyoto Fusioneering | |
| 2024-04-11 | Series C extension (1st) | ¥1.56B エクステンションで15.6億円 | Kyoto Fusioneering | |
| 2024-04-11 | Series C extension | ¥1.56B 15.6億円 | Company release (PR TIMES) | |
| 2024-07-23 | Series C extension (2nd close) | ¥1.07B 2nd closeで10.7億円 | Kyoto Fusioneering | |
| 2025-09-09 | Series C extension (final) | ¥1.45B equity; ¥9.38B incl. debt facilities デットファイナンス（融資枠を含む）との合計93.8億円 | Kyoto Fusioneering | |
| 2025-09-09 | Series C extension (close) | ¥9.38B incl. debt and facilities 合計93.8億円 | Company release (PR TIMES) | |
| 2026-08-24 | Series D (first close) | ¥25.72B (¥16.72B equity + ¥9B debt) 総額257.2億円 | Company release (PR TIMES) |
Key hires & board
| 2026-10-02 | HireExecutive joins Starlight Engine board· Kyoto Fusioneering |
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Milestones
| 2026-05-15 | RecognitionKyoto Fusioneering wins QST order for ITER tritium recovery system mock-up· PR TIMES |
|---|---|
| 2026-07-16 | PartnershipNGK and Kyoto Fusioneering partner on molten-salt FLiBe technology· PR TIMES |
| 2026-08-12 | PartnershipTo build UNITY-3 breeding-blanket facility with Oak Ridge National Laboratory· Kyoto Fusioneering |
| 2026-09-14 | GrantConditionally selected for METI fusion power demonstration subsidy· Kyoto Fusioneering |
| 2026-10-07 | PartnershipKyoto Fusioneering and Daido Steel co-develop vanadium-alloy blanket material· PR TIMES |
| 2026-10-08 | PartnershipNew divertor project with General Atomics (DIII-D)· Kyoto Fusioneering |
| 2026-10-08 | PartnershipUNITY-3 in the US and UNITY-1 for US researchers cited in Japan–US joint statement· Kyoto Fusioneering |
News
| 2026-10-16 | Courtesy call on incoming UK ambassador Colin Robertson 京都フュージョニアリング、コリン・ロバートソン次期駐日英国大使を表敬訪問· Kyoto Fusioneering |
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| 2026-10-08 | New divertor project with General Atomics 京都フュージョニアリング、米国DIII-D国立核融合施設を運営する米国ジェネラル・アトミクスと 新たなダイバータ開発プロジェクトを開始· Kyoto Fusioneering |
| 2026-10-08 | UNITY-3 in the US and UNITY-1 for US researchers cited in Japan–US joint statement 米国でUNITY-3を建設、京都のUNITY-1を米国研究者へ 京都フュージョニアリングとORNLの官民連携が日米共同声明で言及· Kyoto Fusioneering |
| 2026-10-08 | Kyoto Fusioneering starts new divertor project with General Atomics 京都フュージョニアリング、米国DIII-D国立核融合施設を運営する米国ジェネラル・アトミクスと 新たなダイバータ開発プロジェクトを開始· PR TIMES |
| 2026-10-07 | Kyoto Fusioneering and Daido Steel co-develop vanadium-alloy blanket material 京都フュージョニアリング、大同特殊鋼とフュージョン炉ブランケット向けバナジウム合金構造材の製造技術確立に向けた共同開発を開始· PR TIMES |
| 2026-10-02 | Executive joins Starlight Engine board 当社役員のStarlight Engine株式会社 役員就任に関する· Kyoto Fusioneering |
| 2026-09-30 | THE FUSION ERA: in-house gyrotron simulation code THE FUSION ERA – ジャイロトロンの設計と実験のギャップを埋める独自シミュレーションコード開発· Kyoto Fusioneering |
| 2026-09-29 | Kyoto Fusioneering supplies gyrotron system to Quaise Energy for deep geothermal drilling 京都フュージョニアリング、米国Quaise Energyへ深部地熱掘削用ジャイロトロンシステムを供給· PR TIMES |
| 2026-09-18 | Former PM Fumio Kishida visits Kyoto research centre 岸田文雄元内閣総理大臣、上川陽子衆議院議員らが京都フュージョニアリングの京都リサーチセンターを視察· Kyoto Fusioneering |
| 2026-09-18 | Former PM Fumio Kishida visits Kyoto Fusioneering research centre 岸田文雄元内閣総理大臣、上川陽子衆議院議員らが京都フュージョニアリングの京都リサーチセンターを視察· PR TIMES |
| 2026-09-15 | Project ALBION video Project ALBION Video· Kyoto Fusioneering |
| 2026-09-14 | Conditionally selected for METI fusion demonstration subsidy 経済産業省の「令和７年度補正フュージョンエネルギー発電実証推進事業補助金」において、条件付き採択事業者に選出· Kyoto Fusioneering |
| 2026-08-24 | Kyoto Fusioneering speeds up commercialisation work 京都フュージョニアリング、フュージョンエネルギー商用化に向けた開発を加速· Kyoto Fusioneering |
| 2026-08-24 | Kyoto Fusioneering accelerates development toward commercial fusion 京都フュージョニアリング、フュージョンエネルギー商用化に向けた開発を加速· PR TIMES |
| 2026-08-12 | UNITY-3, world-first blanket test facility, to be built with ORNL 京都フュージョニアリング、増殖ブランケットを実証する世界初の施設「UNITY-3」をオークリッジ国立研究所と建設へ· Kyoto Fusioneering |
| 2026-08-12 | Kyoto Fusioneering to build UNITY-3 breeding-blanket facility with Oak Ridge 京都フュージョニアリング、増殖ブランケットを実証する世界初の施設「UNITY-3」をオークリッジ国立研究所と建設へ· PR TIMES |
| 2026-07-16 | NGK and Kyoto Fusioneering partner on molten-salt FLiBe technology NGKと京都フュージョニアリング、フュージョンプラント向け溶融塩FLiBe技術で連携· PR TIMES |
| 2026-05-15 | Kyoto Fusioneering wins QST order for ITER tritium recovery system mock-up 京都フュージョニアリング、ITERテストブランケットシステム向けトリチウム回収・計量システムのモックアップ開発をQSTから受注· PR TIMES |
| 2025-09-09 | Series C extension closes; ¥9.38B secured incl. debt シリーズCラウンド（エクステンション）を終了し…合計93.8億円の資金を確保· Kyoto Fusioneering |
| 2023-05-17 | ¥10.5B Series C シリーズCで総額105億円の資金調達を実施· Kyoto Fusioneering |
Founder profiles: Taka Nagao, Satoshi Konishi
Funding rounds in 2026
Amounts are the full announced figure. Grey amounts aren't counted in equity totals. † includes debt, grants or other non-equity (hover for detail).
| Date | Company | Stage | Amount | Investors | Sector |
|---|---|---|---|---|---|
| 24 Aug 2026 | KFKyoto Fusioneering | Series D | ¥25.72B† | IMM Investment JapanSiteGround CapitalGX Acceleration Agency +9 | Energy & FusionDeep tech |