sappings

In fact, the strategic plan for the capture of the town has been much like the plan adopted by the Japanese forces at Port Arthur -- they have forced their approach by sappings.

The New York Times Current History of the European War, Vol 1, Issue 4, January 23, 1915 Various

By early afternoon the clouds lifted, and with glasses we were able to distinguish fresh sappings of the Japanese infantry nearer to the German redoubts.

The New York Times Current History of the European War, Vol 1, Issue 4, January 23, 1915 Various

He had no genius for the tactics of intrigue; your reconnoiterings, and marchings, and countermarchings, sappings, and minings, assaults, sometimes surrenders, and sometimes repulses.

Coningsby Benjamin Disraeli 1842