A plain first path: emergency fund, NISA, one low-cost global fund, automation — with the mistakes to avoid.
For a complete beginner, the simplest path is: build an emergency fund, open a NISA at a low-cost broker, automate a monthly purchase of one diversified low-cost index fund, and review once or twice a year.
The recommended starting point for a Japanese-speaking beginner investing a modest monthly amount is the NISA recurring allowance, funding one low-cost all-country equity fund. First secure liquid savings and clear high-interest debt; then open a NISA at a broad, low-cost broker such as Rakuten, SBI, Matsui, or Monex; then automate a monthly purchase you can sustain through job changes and market falls.
A sustained ¥5,000 a month is better than ¥100,000 you are later forced to stop and sell. The goal is a simple, automatic habit you can hold for years, not a clever portfolio.
The common early mistakes are avoidable. Do not invest your emergency fund — it needs reliability, not returns. Do not buy multiple overlapping thematic funds; one broad fund usually does the core job with less duplication and cost. Do not pick funds by last year’s return, which is an unreliable guide to the future. And do not treat NISA as risk-free — it removes tax, not the possibility of loss.
If you are a US taxpayer, pause before buying a Japanese mutual fund and review PFIC rules first. If you may leave Japan soon, understand that NISA generally cannot continue abroad.
Brokerage (NISA/iDeCo) · Rakuten Securities
A leading low-cost brokerage for NISA and index-fund investing, integrated with Rakuten points and Rakuten Bank.
Fees: Many domestic funds and trades are low- or no-commission — verify current fee schedule.
Brokerage (NISA/iDeCo) · SBI Securities
Japan’s largest online brokerage by accounts, with a very broad low-cost fund lineup and full NISA/iDeCo support.
Fees: Many trades and funds are low- or no-commission — verify current fee schedule.
Brokerage (NISA/iDeCo) · Monex
An established online brokerage often chosen for US-stock access and research tools, with NISA and iDeCo support.
Fees: Commissions vary by product; some funds/trades are low-cost — verify current schedule.
This is education, not a recommendation. Most beginners research low-cost, broadly diversified index funds — for example all-country (全世界株式) or S&P 500 trackers — rather than picking individual stocks, because low fees and diversification are within your control while returns are not. Understand that values fall as well as rise, match the risk to your time horizon, and never invest money you may need soon.
Generally yes, if you are a tax resident of Japan (with a My Number) and at least 18. NISA is tied to residency, not citizenship, so most foreign residents qualify — with two big cautions: US citizens and green-card holders face US tax complications with Japanese funds, and NISA generally cannot continue after you leave Japan. Confirm eligibility and the current rules on the FSA site and with your chosen brokerage.