At the AI Builders Brisbane July 2025 Meetup, I gave a 2025 edition of my 'How Not to Translate a Videogame' talk from 2019. The talk explored how recent advances in AI, especially agentic capabilities, improved the scope and quality of the outcomes possible from "hobby-level" effort into automated translation of a relatively obscure Japanese visual novel, '12Riven' - the final game in a series of four that all otherwise have official or fan translations available.

The 2019 approach

The approach in 2019 relied on a pipeline of realtime text detection, recognition, and machine translation to produce a translated version of text from the game as it appeared. That translated text would then be displayed in a seperate window. Even with the use of an Azure Custom Translate model (trained off the fan translation of an earlier game in the series), machine translation quality was variable, and the ergonomics of the whole setup were simply too awkward to apply for the entirety of a 30,000+ line visual novel.

The 2025 approach

In the session, we looked at how the use of Claude Code significantly improved the approach and outcomes in a second, "vibe translated" attempt. Agentic assistance greatly simplified the process of reverse engineering the game script and generating extraction/reinsertion and repacking utilities, enabling a translation to be applied directly to the game. The switch from machine translation of isolated lines to an llm-based, 'context-aware' translation of batches in sequence, including a multi-pass review process and automatically-maintained translation consistency guide, resulted in a (subjectively) greatly improved quality of translation. The development of a parallel agent framework enabled reliable, unattended, and high throughput translation of the script, in a manner that took advantage of the Claude Code Max subscription usage windows to perform an estimated $1,100 AUD of token usage at zero incremental cost.

Although much code was produced and executed in the process of reverse-engineering, extraction, translation and repacking of the game - no code was written by me. I noticed various suboptimal implementations as I reviewed some of the scripts, prompts, and intermediate outputs while pulling together the slides; but when vibing, "we run the code - we don't judge". The hard work was handled by my good friend Claude Code.

Despite the fact that at first glance this appears to be an excellent and compelling approach towards making a Japanese game accessible to an English speaker, I have to acknowledge that I have no idea of how good or bad the translation output actually is, since I can't read Japanese to verify it. This ties in to a thought I have around cautioning the use of AI to do something you aren't able to do yourself. Beyond the risk involved in taking a dependency on a volatile third-party, it's worth considering that you are unlikely to be able to properly evaluate the quality, completeness, or robustness of an artefact related to a domain you do not understand. This is fine for hobby-level or personal projects, and I will happily use this translation to play the game in the knowledge that it might not be accurate. For anything professional, quite appropriately, a professional translator is called for.

A sample of the translated script in game can be seen in the video below. A few obvious issues, like broken speaker detection and lack of text breaking, were left unfixed to demonstrate that beyond replacing the script, there will typically be fixes required to get a nicely functioning fan translation. I reckon Claude and I can crack those without too much trouble though 😎

Although it is not the right way to translate a videogame, this is adequate for my purposes. It will allow me to acheive one of my life's two dreams - completing the Infinity series - so that I may return my full focus to the other: becoming moderately good at the piano.

Overall, an excellent result.

Slides (63): PDF