Thanks to the tip from a Finnish reader to the blog some info on tanks of the inter-war era [WW1 & WW2] possessing multiple turrets.
I was aware that these armor designs existed but not in such numbers. Seems having armor [tanks] with multiple turrets was all the rage at one time.
A design feature [multiple turrets] at least antiquated and felt to be passe' from 1939 onward.
Merely for the Soviet Union alone among the world powers we have these versions of tanks all with multiple turrets:
1. T-100. "The T-100 tank sported two turrets placed on a long chassis. The front turret, mounting a 45mm antitank gun, was placed at a lower elevation than the other, and as such had a limited area of fire. The top turret, mounting a 76.2mm gun, was able to turn a full 360 degrees."
T-100 Soviet tank the wiki entry for same suggests the smaller gun was anti-tank and the large main gun used primarily to defeat enemy fortifications, etc.
2. SMK. "The SMK's armament was a short 76.2 mm gun in the upper centrally placed turret and a 45 mm weapon in the forward turret."
SMK that main gun able to counter and defeat enemy armor, the smaller gun used primarily against enemy infantry?
3. T-35. "By July 1932, a prototype of a 35 ton tank with a 76.2 mm tank gun was completed. The first prototype was further enhanced with four smaller turrets, two with 37 mm guns and two with machine guns."
T-35 with five turrets. NOT all so readily discernible in this image!
4. T-28. "The T–28 had one large turret with a 76.2mm gun and two smaller turrets with 7.62mm machine guns"
T-28 tank those two turrets located forward of the main gun able to traverse right and left independently of one another.
Armor design and engineering development in a rapid state of ferment in those inter-war years [1919-1939]. Indeed, a tank mostly at the time of initial production already antiquated by more sophisticated designs on the drawing board or existing as experimental or prototype versions.
"The prototype T-100 tank was briefly tested alongside the other designs in the Soviet invasion of Finland in 1939 without success. It was never put into production, due to the archaic design concept, poor mobility and the availability of a far superior alternative, the KV series."