There were substantially three ways by which the Union army might advance: one lay along the west side of the triangle to Columbia, there attacking the enemy’s left wing; another to march directly south to Shelbyville, and fall upon the enemy’s center; a third, to advance by two roads, cutting the base of the triangle about midway between the enemy’s center and extreme right. A fourth route was possible, along the eastern side of the triangle to McMinnville; but if the enemy’s right was to be attacked, the Manchester roads were every way preferable, as being more direct. General Garfield’s selection was the third route. His plan was to throw a heavy force forward on the road to Shelbyville, as if intending to attack the rebel center. Then, under cover of this feint, swiftly throw the bulk of the army upon the enemy’s right, turn the flank, cross Duck River, and march swiftly to the enemy’s rear, threatening his supplies, thus compelling Bragg to fall back from his tremendous stronghold at Shelbyville, and either give battle in the open country or abandon the entire region. On the 23d of June the movement was begun by the advance of General Granger’s division toward Shelbyville. At the same time a demonstration was made toward the enemy’s left, to create the belief that feints were being made to distract the enemy’s attention from what would be supposed the main attack on Shelbyville. Meanwhile the bulk of the army was advanced along the two roads leading to the middle of the enemy’s right—the east road leading through Liberty Gap, and the west through Hoover’s Gap, a defile three miles long. On the twenty-fourth a terrible rain began, continuing day and night, for over a week. It rendered the wretched roads almost impassable, and terribly increased the difficulties of the army. The artillery sunk hub-deep in the almost bottomless mire. Great teams of twelve and fourteen powerful horses “stalled” with small field-pieces. Never a minute did the rain let up. The men’s clothing was so drenched that it was not dry for two weeks. The army wagons, hundreds in number, carrying the precious bacon and hard-tack, stuck fast on the roads. So fearful was the mire that on one day the army only advanced a mile and a-half.