On the third article, I’d like to write as “one person standing on the private‑sector side” looking at fusion, and describe the landscape that I see. I am currently in a position where I am trying to build a VC firm in Japan focused on fusion and space, and every day I follow the moves of startups and investors around the world while thinking about what kind of ecosystem we can create in this country.

First, there is a basic point I want to make clear: fusion has already become a venture‑investment game. Globally, cumulative private investment into fusion startups has reached on the order of 10 billion dollars, and “unicorns” such as Commonwealth Fusion Systems, TAE Technologies, and Helion Energy alone have raised several billions. On top of that, from 2025 onward, new rounds worth hundreds of millions of dollars have been closing one after another, and through 2025–26 a fresh wave of large fundraisings is underway. The very fact that this much risk capital is flowing in at a stage when the probability of technical success is still opaque speaks to the magnitude of the expected upside if it works and the potential to rewrite the energy system itself.

If you look at who the investors are, it becomes clear that this field is not just about “romantic capital.” On the venture capital side, players that specialize in deep tech, such as Breakthrough Energy Ventures, DCVC, and Lux Capital, are playing central roles. Alongside them you see big tech firms like Google and Microsoft, energy majors such as Chevron and Equinor, and individual tech leaders like Bill Gates and Sam Altman. They are assembling a portfolio that is completely different from SaaS or fintech—“ultra‑long‑term, high‑risk, high‑impact” bets. In doing so, they are, in a sense, trying to rewrite the rules of capital markets to accommodate a wager that says, “Let’s think on a multi‑decade timescale and change planet‑scale externalities.”

On the entrepreneurs’ side, their motivation is not simply to pursue “Nobel‑Prize‑class science.” Many fusion startups are setting explicit commercial goals such as “Instead of traditional gigantic experimental reactors, use privately led, compact reactors to sell power on a timeline that makes business sense.” In that world, the core question is not “Which method has the most romance?” but rather “With which architecture can we connect to the grid at a realistic capital cost and construction lead time?” That kind of highly businesslike discussion is happening every day. Even the choice of technology is effectively being shaped by “the balance of risks and returns that investors and markets are willing to accept.”

Against this backdrop, the Japanese private sector is finally beginning to stake out its own position. For example, Kyoto Fusioneering has raised about 19.1 billion yen with a business model focused not on the reactor itself, but on “balance‑of‑plant” areas such as heat exchange and tritium handling, and is increasing its presence as a component supplier to fusion startups worldwide. Helical Fusion, meanwhile, is pursuing its own path using a stellarator approach, aiming for commercial reactors in the 2030s, and is entering a phase where we can test whether Japan‑origin technologies can compete in the global market. These moves are being supported by the revision of the “Fusion Energy Innovation Strategy” under the Takaichi administration, and are part of a structure that is trying to bundle together public‑ and private‑sector risk‑taking toward the milestone of power‑generation demonstration in the 2030s.

What I personally find most interesting is that—both globally and within Japan—the division of roles over “who takes which phase of risk” is still far from settled. So far, from seed to around Series A, deep‑tech‑focused VCs and a few tech and energy companies have been taking the lead, and beyond that, in the later, larger rounds, sovereign wealth funds, institutional investors, and infrastructure investors are gradually starting to appear. In Japan as well, government‑affiliated financial institutions and corporate CVCs are beginning to show interest, but there are still very few “specialized funds that look only at fusion.” Precisely because of that, people in positions like mine have a wide open space to design “which stage of technology and which companies we provide capital to, and on what time horizon.”

So what stance do I want to take toward this field? What I am currently thinking is to treat “fusion itself” and “the industries that spread out around it” as one continuous spectrum. In other words, I want to be an investor who, instead of looking only at reactor development, takes into scope materials, measurement, vacuum technology, plasma control, power systems, and even policy, regulation, and international standard‑setting, and then asks: “Where does Japan have a comparative advantage, and with which countries and which players should we partner to scale that advantage?” The success or failure of fusion will not be determined by the efforts of a single startup or a single country. It is, rather, a marathon‑like contest over “what kind of ecosystem we can sustain, and for how long.” In that long‑distance race, the question is how many private‑sector flag bearers are willing to take risks from Japan—and as one of them, I want to see how far I can go on my own two feet. That is my honest feeling toward fusion today, seen from the private‑sector side.