Most typical field bunkers built before WWII*
and used during 1939 campaign were for flanking*
fire of one or two machineguns. They were protected*
with earthen embankment against direct fire. *
*
Therefore, they should be placed on flanks of*
predicted attack path, showing earth-covered sides*
to an enemy, and heading towards an attack path.*
*
Many such bunkers were built in months directly*
preceding the war. In several cases they helped to*
stop the Germans for some time, most notably near*
Mlawa.*
*
_____________[description by PIBWL]*