When cash, time deposits, and JGBs are the right tool, and when investing for growth makes sense.
Save money you may need soon in cash or deposits; invest only money you will not need for years and can watch fluctuate. Matching each goal to a time horizon is the core decision.
Money sits on a spectrum from most liquid and stable to least. Ordinary deposits give instant access and stability but little return. Time deposits fix a rate for a term, adding predictability at the cost of early-withdrawal restrictions. Retail Japanese Government Bonds (JGBs) offer government-backed principal, a ¥10,000 minimum, monthly issuance, and a minimum-rate provision, but low expected return and an early-redemption adjustment. Investments — shares, funds, bonds beyond JGBs, and property securities — offer higher expected return but fluctuating value and no principal guarantee.
The right tool is not the highest return; it is the one that matches when you will need the money and how much fluctuation you can tolerate along the way.
Cash feels safe because its yen number does not fall. But if prices rise 2% while your deposit earns near 0%, the same yen buys less next year — a real loss in purchasing power even though the balance is unchanged. This inflation risk is the main argument for investing money with a long horizon, where growth assets have historically outpaced cash over long periods (without any guarantee they will continue to).
The mirror-image mistake is investing money you will need soon: a temporary market decline can force a sale at a bad price. Both errors come from mismatching money to its time horizon.
A house deposit needed in three years generally stays in cash or short-duration safe assets, because a 30% equity fall just before purchase would be devastating. Retirement money needed in thirty years can tolerate equity volatility, because there is time to recover. A single allocation for every goal is a common mistake: separate your emergency fund, near-term goals, and long-term goals, and use a different tool for each.
A practical split: keep several months of expenses plus any goal due within about three years in deposits; invest only the surplus you will not touch for years.
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.