Why people invest, saving vs investing, the Japanese system (NISA, iDeCo, taxable), brokerages and products, and a beginner order of operations.
For most Japan residents, the sensible path is: build cash reserves and clear expensive debt, open NISA at a low-cost broker, automate one diversified low-cost index fund, and add iDeCo, individual stocks, or foreign products only once the core and tax admin are under control.
Saving preserves nominal yen and provides liquidity; investing exchanges certainty for the possibility of growth, at the cost of fluctuating value and no principal guarantee. Cash is right for emergencies and near-term spending, but over long periods its purchasing power can erode to inflation, which is the main case for investing money you will not need for years.
A sensible order of operations for most residents: (1) maintain enough liquid cash for foreseeable expenses; (2) repay expensive debt; (3) capture any employer match or unusually good corporate pension; (4) open a low-cost brokerage and NISA; (5) automate a sustainable monthly purchase of one diversified index fund; (6) consider iDeCo once you understand its deduction, lock-up, and retirement taxation; (7) add individual stocks or foreign products only after the core and tax admin are under control.
You invest through a securities company (brokerage), inside one of a few account types. NISA is a tax-free wrapper: since 2024 it allows ¥1.2m recurring plus ¥2.4m growth per year, an ¥18m lifetime limit, and indefinitely tax-free qualifying gains — usually the first account to fund. A taxable "specified" account holds anything beyond NISA, taxed at 20.315% but with loss offsets. iDeCo is a private pension: contributions are deductible, but money is locked until retirement age.
Inside the account, most beginners research broad, low-fee index funds (all-country or S&P 500 trackers) rather than individual stocks. A single global fund can be a complete equity core; adding bonds or cash lowers volatility according to how much loss you can tolerate.
Two cross-border cautions matter most. US citizens and green-card holders face PFIC reporting problems with Japanese funds and should get specialist advice before buying. And NISA is a residents’ benefit — leaving Japan generally means you cannot continue it, so plan the exit before building a large balance. Everyone should also treat tax-free as not risk-free: investments in NISA can and do fall.
From here, the cluster’s other pages go deeper: how to start, saving vs investing, risk, diversification, compounding, the full NISA guide, accounts and taxes, product categories, broker comparisons, and pages for foreign residents and US taxpayers. Follow the beginner path first, then explore the topic that fits your next decision.
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.
Be very careful. Japanese mutual funds and ETFs are usually PFICs (Passive Foreign Investment Companies) for US tax, which triggers punitive US taxation and heavy Form 8621 reporting — and the NISA tax exemption does not apply to the US. Many US persons in Japan avoid Japanese pooled funds and instead hold US-domiciled assets, but rules are complex. Get advice from a cross-border US/Japan tax professional before investing.