The three commanders killed were key to operations including smuggling, tunnel construction and capturing the Israeli soldier Gilad Shalit in 2006, the BBC's Yolande Knell reports.
With stealth considered key to the operation it was intended that any bunkers and camps located during the patrol phase of the operation would not be destroyed until after the ambush phase.
Twin ties of blood or friendship and extremism was a pattern repeated again by the Bakraoui brothers, and apparently key to the operation of a vast and brutally ambitious network of militants under the noses of an intensive European police operation.
The project helped a factory in Suzhou to gear up to make the little plastic lenses that are the key to the operation's success.
The key to his operation is not theology - he preaches a relatively middle-of-the-road, intellectually undemanding form of evangelism - but organisation.
The key to the operation was a set of standardised monthly reports filed by every GEC business: eight ratios (profit margin, staff turnover and so on) on the first page; raw figures on the second page; a written commentary thereafter.
His tools are bookbinder's glue, a metal instrument called a micro-spatula, a tongue-depressor-like implement called a bone folder, an X-Acto knife, rice paper, book cloth, acid-free tissue, and quantities of rubber bands, which he says are key to the operation.
The key to the operation of a cyclotron is the fact that the orbits of ions in a uniform magnetic field are isochronous; that is, the time taken by a particle of a given mass to make one complete circuit is the same at any speed or energy as long as the speed is much less than that of light.
This steering wheel light bar is key to the operation.
As environments and tasks become increasingly complex, it eventually boils down to adaptation, which is a key to sustained operation and to long-term viability.
