Another glance at the map will show that, almost halfway between Shabatz and Belgrade, the Save takes a peculiar little loop into Serbian territory, forming a narrow strip of Austrian territory projecting into Serbia. Naturally, this little tongue could be commanded by the Serbian guns without first crossing the river, since the Austrians could only operate here by marching down in a narrow column between the two sides of the loop formed by the river. Such a force, however, could be immediately flanked by the Serbians from their side of the river. This peculiar peninsula, known as the Kupinski Kut, was chosen as the point at which the first crossing should be made. CHAPTER LII SERBIAN ATTEMPT TO INVADE AUSTRIAN TERRITORY It was the night of September 5, 1914. So secretly was this movement planned and begun that the Serbian field officers did not themselves know what was to be undertaken when their forces arrived on the banks of the river at the Kut on the nights of September 5 and 6. The marches were made at night, to hide the movement as long as possible from the Austrian aeroplanes, which occasionally whirred their flight over Serbian territory. At one o'clock in the morning of September 6, 1914, the first troops of the invading expedition embarked on the barges lined up along the river bank. A screening force having been ferried across, to protect the ford against possible attack, the construction of a pontoon bridge was begun at Novoselo, while farther up some flour mill floats were utilized for a second bridge. It was an ideal place for a crossing. Farther up, at the neck of the isthmus, was an old river bed, where the Save had once cut a straight channel. This was now full of stagnant water, while between it and the ford the ground was covered with thick timber. The stagnant water, while not very deep, afforded somewhat the same protection that a wire entanglement would, and the woods served as a screen to the advance guard of the Serbians stationed there to guard the crossing. Not far distant, farther up in Austrian territory, was a small town, Obrez. After the Serbian army had crossed safely, it set to work clearing the timber away, it being no longer necessary to screen themselves from view, and a strong line of trenches was thrown across the neck of the isthmus, thus effectually protecting the ford for retreat, should that be necessary. At this moment two regiments of infantry and a battery of artillery of the enemy appeared and attempted to oppose the further advance of the Serbians, but when the Serbian guns began shelling the forest opposite, this force fled in the direction of Obrez. Then the left of the Serbian force worked its way around toward the town itself and, after firing some dozens of shells, entered it and drove the Austrians still farther on.