Now observe this map.

Erzerum isn't invested by a long chalk.
The Russians are round it in a broad half-moon.

That means that all the west, south-west, and north-west is open and undefended by trench lines.

There are flanks far away to the north and south in the hills which can be turned, and once we get round a flank there's nothing between us and our friends ...

I've figured out our road,' and I traced it on the map.