Strong legal tenant protection: ordinary leases are renewable and landlords need a justifiable reason to refuse renewal.
A large, well-developed furnished 'monthly mansion'/serviced-apartment market lets newcomers land softly with no key money, no deposit and no Japanese guarantor.
Universal statutory health insurance with comprehensive coverage and free choice of provider (no formal GP gatekeeping or referral system)
Standard patient share is 30% of costs, with an out-of-pocket cap through the high-cost medical expense benefit

Watch out for

High move-in costs: deposit, non-refundable key money (reikin), agency fee, guarantor-company fee, fire insurance and first month commonly total 3-6 months' rent.
Most landlords require a guarantor or a paid rent-guarantee company, and some properties still decline foreign tenants, so screening can take time.
Short-stay visitors and tourists cannot use public insurance and pay the full bill out of pocket - private travel/health insurance is essential
Public health-insurance enrollment is tied to registering as a resident at the local municipal office; foreign residents must report their address shortly after moving in

Cost of living

Tokyo

€1,700–€2,900/mo