World Moyamoya Day, also known as Moyamoya Awareness Day, is observed worldwide every May 6. Established in 2013, the day aims to support patients and their families affected by moyamoya disease, a rare cerebrovascular condition characterized by the narrowing of arteries in the brain. The disease, first identified in Japan in the 1960s, leads to the development of collateral blood vessels that resemble a "puff of smoke" on angiograms. Symptoms can include transient ischemic attacks, strokes, and cognitive impairments, affecting both children and adults, with a higher prevalence in women. The only effective treatment to restore blood flow is surgical intervention. On this day, individuals are encouraged to learn about moyamoya disease, share information, and support organizations focused on research and patient care, using hashtags like #WorldMoyamoyaDay and #MoyamoyaDay on social media.