What puzzles many world talents, who start life in Japan, is difference in practices of apartment rent from the ones in their home countries. Many talents have questions around key money and security deposit. In fact, there are regional differences even domestically within Japan, e.g. in how many months of deposit is required and how deposit is refunded at termination of rent. It is therefore not straightforward even for a Japanese to explain them in Japanese.
In order to ease such a challenge, Japanese government, Ministry of Land, Infrastructure, Transport and Tourism (MLIT), provides multi-lingual guidebook to explain practices and contracting terms of apartment rent in Japan here. Please let me describe this MLIT web page structure briefly, as the page is in Japanese and there appears to be no corresponding English page.
The page consists of two parts: its upper part is for landlords and real estate agents, providing a guideline document to streamline renting an apartment to non-Japanese tenants. The document is in Japanese, while attachments including renting contracts etc. are provided in eight major languages.
The page’s lower part is for non-Japanese tenants and provides a concise guidebook on apartment hunting, rent agreement contract and notes (e.g. what-not-to-do after move-in) in 25 pages. The guidebook is available also in eight languages (as of May 2019: English, simplified Chinese, Korean, Spanish, Portuguese, Vietnamese, Nepali and Japanese). It covers the key money and security deposit as well. This guidebook should be recommended as tips to your friends who are puzzled by the difference.
Link: Guidebook on renting an apartment in Japan (English version)
Please find other language versions toward bottom of the following page.
Link: MLIT’s page (Japanese)