In Japan, Article 21 of the Japanese Constitution guarantees freedom of expression and prohibits formal censorship. What censorship does exist is often carried out through Article 175 of the Criminal Code of Japan. Historically the law has been interpreted in different ways—recently it has been interpreted to mean that all pornography must be at least partly censored; however, there have been very few arrests based on this law.
As publishing became more popular in the Edo Period, the Tokugawa shogunate began to turn to censorship. Initial targets included Christianity, criticism of the shogunate, and information on the activities of the Tokugawa clan. With the Kansei Reforms, any material deemed to be disturbing the traditional way of life, as well as luxury publications came under scrutiny. Under the Tempō Reforms, printing blocks of erotic literature, as well as the novels of Tamenaga Shunsui and Tanehiko Ryūtei were among those seized.
After the Meiji Restoration in 1868, which marked a major political shift in Japan, the government began heavy censorship of Western ideas, pornography and any political writings critical of the Emperor of Japan and government, wanting to control the spread of information. Censorship of materials increased from this point, often using ongoing wars to increase police powers and penalties. In 1928, the death penalty was added to the list of punishments deemed acceptable for certain violations. This continued, eventually to the Information and Propaganda Department (情報部 Jōhōbu?) being elevated to the Information Bureau (情報局 Jōhō Kyoku?) in 1940, which consolidated the previously separate information departments from the Army, Navy and Foreign Ministry under the aegis of the Home Ministry. The new Bureau had complete control over all news, advertising and public events. The following year revision of the National Mobilization Law (国家総動員法 Kokka Sōdōin Hō?) eliminated freedom of the press entirely, doing things such as forcing papers in each prefecture to either merge into one paper or cease publication, with all articles by the paper having to be screened by government censors before they could be published.