Thus, B became a stateless person without a nationality of any State.189 While waiting for contact from the Chinese Embassy, B’s period of stay in Japan also expired. B was overstaying for more than 10 years but voluntarily appeared at a regional immigration bureau in 2007 and requested special permission to stay. In 2010, B was granted special permission to stay with nationality noted as “Stateless”. After obtaining the permission to stay in Japan, B proceeded to restore B’s nationality at the Embassy of China, and B currently holds Chinese nationality. When B became stateless in Japan, having already lost residential status, B could not receive any social welfare benefits including health insurance and was not allowed to work. 190 B was in a predicament with the tightened immigration control of irregular stayers under the “Five year plan to reduce irregular stayers by half”, which began in 2004 with the Immigration Bureau and the Police Agency. Before obtaining permission to stay in Japan and restoring Chinese nationality, B tried to open a bank account at a local bank by showing B’s (former) alien registration certificate; however, B was unable to open an account because B’s alien registration certificate, which showed “Stateless” in the nationality section, was regarded with suspicion. 3. Possible size of Category F (1) The risk of statelessness in undertaking procedures to change (renounce) nationality Category F covers statelessness that arises temporarily or lasts for a long-term when a person renounces his or her previous nationality for the purpose of naturalization or a nationality recovery process which then fails and the person cannot acquire a new nationality immediately. Case 11 (hereinafter referred to as “naturalization failure case” in this section) is a typical case in terms of naturalization-related ones. It occurs for example when a person applies for naturalization to country α which does not allow dual nationality, he or she is requested to renounce the nationality of country β, and when he or she renounces country β’s nationality, naturalization permission is suspended or disapproved for circumstances that arose or are revealed before the formal grant of naturalization. Under the current naturalization related practice in Japan, applicants are urged through the relevant legal affairs bureau to acquire a certificate of having renounced their current nationality when their naturalization is about to be approved, i.e., has “informally” been approved. They are requested to submit this document by the formal notification of approval of naturalization. 189 On details about how B became stateless, see the case of Lee Man-Biu below. Chen Tien Shi, Wasurerareta Hitobito, Nihonno “Mukokuseki” Sha [Forgotten People: “Stateless” in Japan] (Akashi Shoten, 2010), pp. 74-77. 190 In reality, however, the control of irregular stayers from the late 1990s to early 2000s was not as strict as it is today, and B was able to make a living by running his own business. 92