Gigli saw

A Gigli saw is a flexible wire saw used by surgeons for bone cutting. A Gigli saw is used mainly for amputation, where the bones have to be smoothly cut at the level of amputation.

The saw was invented by Italian obstetrician Leonardo Gigli to simplify the performance of a lateral pubiotomy in obstructed labour.

Gigli saws were sometimes hidden in the clothing of British secret agents during World War II.

According to a recent episode of What History Forgot on the American Heroes Network, Gigli saws also were sent to British POWs held by the Germans, in a little known escape scheme. A British company licensed to produce London versions of the board game Monopoly by Parker Brothers, the manufacturer, worked closely with Military Intelligence to hide saws and other tools, money, and maps inside the double-thick boards. Apparently, every RAF air squadron had officers trained in escape. When they were captured, they knew where to write to announce that they were now prisoners-of-war, and where they were being held. In return, these officers would be sent one of the special Monopoly games, via the International Red Cross care package. When the escape-trained officer opened it and saw that the board had a dot on the parking square, he knew to take it to the most private place he could find and open it to access its contents. Should the officer and the others he chose to escape with him be successful, neither they, nor other POWs he may have passed the tools onto knew where the saw, file, money and maps came from.

This was such a top-secret operation that after the war, all saws and other tools, along with any records that might remain were incinerated by MI-6.

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Wikipedia