In 2007, the Tokyo Guidelines for the man-agement of acute cholangitis and cholecystitis (TG07) werefirst published in theJournal of Hepato-Biliary-PancreaticSurgery. The fundamental policy of TG07 was to achievethe objectives of TG07 through the development of con-sensus among specialists in this field throughout the world.Considering such a situation, validation and feedback fromthe clinicians’ viewpoints were indispensable. What hadbeen pointed out from clinical practice was the low diag-nostic sensitivity of TG07 for acute cholangitis and thepresence of divergence between severity assessment andclinical judgment for acute cholangitis. In June 2010, weset up the Tokyo Guidelines Revision Committee for therevision of TG07 (TGRC) and started the validation ofTG07. We also set up new diagnostic criteria and severityassessment criteria by retrospectively analyzing cases ofacute cholangitis and cholecystitis, including cases of non-inflammatory biliary disease, collected from multipleinstitutions. TGRC held meetings a total of 35 times aswell as international email exchanges with co-authorsabroad.