The Ministry of Economy, Trade and Industry sounded the alarm in 2018, drawing widespread attention to the “2025 Digital Cliff.” According to the Ministry, the growing complexity and increasing hermeticism of legacy systems was a driver not only of ballooning upkeep and maintenance costs, but of losses at the operational and business levels as well. Yet even today, in 2026, the dead weight of legacy systems is making itself felt in many cases.


The optimal approach differs depending on the company, the business, and the system. For businesses and operations that are not changing significantly despite the changing times, the first approach can be effective, but for systems facing circumstances where the market environment or business strategy is experiencing massive change and the ideal form of business is being reassessed, the third approach is needed. Uzu explains, “We often hear from clients that are in dire straits because they haven’t done the work of figuring out what approach they need and instead have launched a scattershot array of minimalist projects to solve system problems, resulting in a proliferation of new legacy systems.”

For reform activities that seek to integrate operational, data, and systems issues over the medium-to-long term with an eye on future business, the third approach is the only option. Such activities demand not replacement of individual systems, but a sustainable reimagining of growth-promoting operations, data, and systems, with stable coherence across all domains. Efforts in this direction must be driven not only by IT departments or the departments that actually use the systems, but by the entire company, including top management. “Enterprise architecture (EA)” plays a vital role in this.


“By utilizing EA as a framework,” Uzu explains, “companies can take a comprehensive and organization-wide view of their operations, data, and systems, anticipate and prevent the disagreements that arise between stakeholders, and lower the hurdles to ensuring operational and systemic coherence while reforms are in progress. This provides a foundation for promoting sustainable modernization for the company as a whole.”

With that in mind, what is actually important for the realization of “sustainable modernization”?

“The essence of modernization is eliminating existing technical liabilities so your company can maintain medium-to-long-term competitiveness. In other words, modernization is not a question of ‘do it once and you’re done,’ but of implementing reforms over and over in accordance with environmental changes. To do that, you need to establish the most efficient systems possible to ensure that you’re minimizing workloads and implementation times.”
Such streamlining, however, is often hampered by the difficulty of analyzing current conditions. Legacy systems that have been in operation for long periods of time often end up mixing architectures from different eras because of the cumulative effect of repeated expansions and rebuilds, and the result is often massive and unwieldy systems encompassing millions of lines of code. Personnel who understand the once-current design diagrams are lost to retirement or turnover, and once systems become black boxes, it can take years to make sense of them. This is the biggest factor undermining the agility of business.
A further obstacle is the burden of testing processes. According to statistics from the Information-Technology Promotion Agency, Japan (IPA), testing processes account for approximately 30% of standard system development. In modernization where continuity of existing functions is required, this percentage can be even higher, creating a barrier that discourages ongoing reform.

“Generative AI is one pathway to solving these problems,” Iwamatsu claims. “By combining generative AI with the program analysis technologies NRI has cultivated already, it is possible, even when design specifications don’t reflect reality, to use program code to generate the definitions of data to be included in specifications, as well as other information that requires a high level of abstraction, such as the business requirements underlying implementation. At NRI, we started experimenting with this in 2023 and began trials on actual projects in July 2024.” In actual practice, these methods have been employed on some finance projects, where they have substantially mitigated workloads relative to past projects conducted manually.

“When we think about sustainability,” Uzu explains, “legacy modernization is a long and winding road.” In some cases, the roadmap can be around ten years long, and one of the secrets of medium-to-long-term success appears to be breaking this long roadmap down into blocks of one or two years and chipping away to accumulate successes. Uzu continues, “The important thing here is the length of the blocks. If they’re too short, it’s easy to fail for lack of time, but if they’re too long, management policy changes and staff reshuffling can make it harder to get everything done.”

Another important factor seems to be having partners that can act as close allies along the journey.

“When I join client projects as a consultant,” Uzu says, “I participate with the mentality that I am not an NRI employee coming from outside, but a client employee with NRI expertise. To achieve this, I thoroughly research the client’s situation in advance. I also adopt the mindset that I need to be a half-step ahead from the client’s perspective. Being behind the client would be out of the question, but if I’m too far ahead, they won’t understand me.”

In closing, Uzu observes that ultimately, it is “human and organizational problems” that are at the root of legacy systems. Adopting the proper approach to these problems may be the most important key to success.