The Japanese-Language Proficiency Test, N5 (easiest) to N1. The official site holds the levels, sections, dates, fees and approved test centres — go there rather than to a summary. Held twice a year, July and December, since 2010, and you do not need to be enrolled anywhere to apply.

For when you cannot wait for the next JLPT sitting. It runs several times a year, and its Q levels map onto the JLPT's N levels closely enough that employers accept a Q2 in place of an N2. Less widely recognised, and useful precisely because the result arrives in weeks rather than months.

Test centres are approved organisations, not anywhere that offers classes. In Tamil Nadu that is ABK OTS Dosokai, which runs NAT-TEST there too. Find yours through the official JLPT site — seats are limited and the application window is a fixed set of dates months before the exam, so missing it costs half a year.

Do at least one sample paper under real timing. The failure mode is not knowledge — it is the listening section, about an hour with no question repeated, where most people lose marks still deciding about the previous question while the next one plays. On the day: pencil only, no pens.

個人事業主 (sole proprietor) is where most people start — fastest and cheapest to register. 合同会社 (GK) is roughly an LLC or LLP: small businesses, consulting, import-export. 株式会社 (KK) is the public-facing limited company — more work to set up and maintain, and what foreign investors and larger customers expect. Moving up as you grow is normal, and is the route one of our hosts took.

Being foreign is not the blocker most people expect. If your visa is valid, you can register a company in Japan. The harder questions are which company form to choose, and which visa you want to hold afterwards.

The Ministry of Economy, Trade and Industry's own English page on the startup visa programme, which is open regardless of nationality. Read this before you read anybody's blog post about it.

English-language support for setting up in Japan at no charge: guidance on the process, startup programmes, sometimes space to work from, and in some offices introductions to investors. Named repeatedly rather than in passing.

A third English-friendly organisation offering consultation at no charge, particularly for technology-led businesses. Worth knocking on before you pay anybody for advice.

Tokyo's own startup and innovation event, run by the metropolitan government. The practical answer to finding a first Japanese customer: cold contact into a Japanese company rarely works, while an expo gives you warm ones in a day. Techno Japan and other trade shows serve the same purpose.

Rules get updated, published guidance lags behind, and different offices interpret the same rule differently. Budget time for it, and confirm with the office that will actually process your case rather than with the page describing it.