Short answers, pulled from the story.
Sergei Eisenstein published the essay titled The Montage of Attractions in 1923. This publication declared editing to be the very nerve of cinema and argued that montage generates meaning within film.
Sergei Eisenstein categorized montage into metric, rhythmic, tonal, overtonal, and intellectual types. He also developed vertical and horizontal montage alongside audio-visual integration methods to manipulate audience perception systematically.
Sergei Eisenstein directed Strike in 1925 and Battleship Potemkin in 1926 to demonstrate his theories in practice. These films featured mass dramas designed to show the collective power of workers rising against oppression.
By the 1930s, Socialist Realism replaced experimental editing with narrative clarity and accessibility for the general public. This shift aligned Soviet production more closely with Hollywood continuity styles despite earlier opposition.
Soviet montage theory reached Britain only in 1928 when Sergei Eisenstein's ideas appeared in Close Up magazine. Filmmakers in Japan remained largely unaware of these concepts during the 1920s despite producing their own films.