The Tokyo District Court on Tuesday rejected an African refugee¡¯s claim seeking to overturn the government¡¯s decision to turn down his naturalization application twice, saying he lacked the necessary Japanese language ability.

The case highlighted the unclear criteria that foreign residents face when they want to become a naturalized citizen, which the plaintiff¡¯s lawyers described as a ¡°black box.¡±

In Tuesday¡¯s ruling, presiding Judge Yukito Okada said the justice minister has the discretion to decide whether to grant citizenship to a foreign national based on the current political and social climate.