Akira Kurosawa had long wanted to make a real jidai-geki, a real period film… One can trace the development of the “real” Japanese period films from the early pictures of Daisuke Ito and Mansaku Itami, through Sadao Yamanaka and Kenji Mizoguchi, to Masaki Kobayashi, and Kurosawa himself. These latter are “real” because they do not stop at simple historical reconstruction, inhabited by stock figures (which is true of costume-pictures all over the world), but insist upon the validity of the past, and the continuing meaning of the historical…
Shichinin no samurai is an epic all right – it is an epic of the human spirit because very few films indeed have dared to go this far, to show this much, to indicate the astonishing and frightening scope of the struggle, and to dare suggest personal bravery, gratuitous action, and choice in the very face of the chaos that threatens to overwhelm.
Like the Russians (Eisenstein, Dovzhenko) to whose epics Shichinin no samurai has often been compared, Kurosawa – here perhaps more than in any other single film – insisted that the motion-picture be composed entirely of motion. The film opens with fast pans of the bandits riding over hills, and ends with the chaos of the battle itself, motion so swift we can almost not see it at all. There is no shot that does not have motion, either in the object photographed, or in the movement of the camera itself. The motion may be small (the quivering nostrils in the long-held image of the village elder) or it may be great (the huge, sweeping frescoes of the charges) but it is always there.
Donald Richie, The Films of Akira Kurosawa, University of California Press, Berkeley-Los Angeles 1965
A great deal is often made of the fact that more than one camera is used to shoot a particular scene. This all started when I shot Shichinin no samurai, because it was impossible to predict exactly what would happen in the scene in which the bandits attack the peasant village during a torrential downpour. If I had filmed it in the traditional fashion, one shot at a time, there was no guarantee that I would be able to repeat a particular action exactly the same way a second time. Therefore, I used three cameras simultaneously. The result was extremely effective.

Akira Kurosawa, L’ultimo samurai. Quasi un’autobiografia, a cura di Aldo Tassone, Baldini & Castoldi, Milano 1995