These outlines of developments in military bomb technology have been written to give the layman some idea, why bomb technology has developed into what it is.
A hollow charge made possible a small charge to make a hole in armour plate was invented in Switzerland in 1937. A cutting charge, used in the WTC in tens of thousands of pieces, was an evolunary model of the principles of a hollow charge from 1950′s.
A Claymore threw steel balls towards the enemy, but was otherwise harmless even from 5 meters distance, was developed in the USA approximately in 1960.
A flank mine is able to direct a narrow pressure wave through AFV flanks from a distance of 20 meters and was more developed in Finland around 1970. Due to efficiency causes, growing part of military explosives deploy improvements utilizing directed explosion energy.
By controlling several layers of the explosion fronts the size of a nuclear bomb has been minimized during the 1960′s (fission – implosion). After that, the control of explosion force in nuclear explosions was developed. Too strong an explosion is sometimes unusable, for example when the enemy have broken too close to friendly cities.
While looking for a bomb with a small size and a strong effect, a pure hydrogen bomb was an obvious solution. When no atomic device is needed for igniting, the size of the hydrogen bomb gets even smaller and the yield (effect) can be set within a wide range, for example between from 1 to 100. This succeeded in the 1980′s, as well as the neutron bomb, which kills only living things and leaves most material untouched.
The former Soviet Union is said to have had more than 500 command centers durable for a small nuke. That led into the developing of different types of bunker busters. A working solution is a nuclear missile that directs 96% of its yield into a thin, all penetrating heat+blast wave forward, tunneling hundreds of meters downwards into solid rock. This type of a hydrogen bomb was developed somewhere in the early 1990′s. Nowadays, both the yield and the direction of the destructive force of a small tactical hydrogen bomb can be somewhat controlled. The amount of fusion-able materials control the yield (effect) and the shape of the charge as well as the initiation arrangements impress the direction of the explosion wave.