It is not possible to obtain a permanent residency in a short period by the real estate investment only. You need to run a feasible business by the real estate or any other business and receive reasonable high salary for years under a working visa status and then you are entitled to the application for permanent residency.
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How can I obtain Japanese permanent residency through the purchase of real estate?
I will graduate from a university in Tokyo next year and want to live permanently in Japan after graduation. My parents are willing to gift me money to purchase some real estate in Tokyo. Will this help me obtain permanent residency in Japan? If not, what are my other options?