geos (株式会社ジオス, kabushiki gaisha jiosu) was one of the big four[1] private eikaiwa, or english conversation teaching companies, in japan. its extensive network of overseas schools made it the worlds largest language school chain.[citation needed] the firm went into bankruptcy in japan on 20 april 2010.[2] its headquarters were in the shin osaki kangyo building (新大崎勧業ビルディング, shin ōsaki kangyō birudingu) in shinagawa, tokyo.[3]