Thirty years ago today, on March 20, 1995 (February 20, 1995 in the lunar calendar), a "sarin" gas case occurred in the Tokyo subway. On the morning of March 20, 1995, the nerve gas "Sarin" occurred in three subway trains in downtown Tokyo, the capital of Japan. Ten people were killed and more than 5000 people were hospitalized for poisoning. This serious terrorist incident in Japanese history shocked the Japanese government. Prime Minister Murayama held an emergency meeting on the same day to discuss countermeasures. Chief Cabinet Secretary Ichiri accused it of being an "organized and premeditated murder operation that killed people." The police mobilized 300 detectives to take to the streets to launch a large-scale search for clues to solve the case. On the 22nd and 23rd, a large number of police searched facilities and homes across the country suspected of being involved in the subway gas incident. According to German newspapers, the poison gas that caused casualties in the Tokyo subway in Japan on the 20th was called "Sarin", whose scientific name is "isopropyl methylfluorophosphate". It is a nerve gas and one of the most toxic phosphates. In 1938, the Germans Schrader, Ambrose, Ruediger, and Van der Linde successfully developed it for the first time. This poison gas was named "Sarin" after five letters of the surnames of the above four people. The Germans quickly discovered the military value of the poison gas and put it into production, but it was not used during World War II. In 1945, Sarin produced in Germany was destroyed. It was only after World War II that this poison gas began to be produced worldwide. It is reported that some time ago, it was used in the Middle East. Generally speaking, sarin is a colorless (also yellow-brown), invisible, odorless gas that can invade the human body through breathing or through the skin and conjunctiva, blocking enzymes in the body and damaging the nervous system. After being invaded by it, symptoms such as miosis, difficulty breathing, bronchoconstriction and severe convulsions will occur. In severe cases, you will suffocate and die within a few minutes. Immediate treatment with atropine, oxime, etc. and artificial respiration will be necessary to save it. However, the poison gas may also cause damage to nerves, brain and liver afterwards. According to the 1925 Geneva Chemical Weapons Convention, the production and use of toxic gases such as sarin are prohibited. However, because the raw materials used in sarin, production processes and some pesticides are similar, it is difficult to ban it. The person standing in the picture is Shoko Asahara, the leader of Aum Shinrikyo