But the problem was that, although the twelve guards were nominally under the command of Lord Qin, he could not rely on them to launch a coup. That's because among these guards, many were more obedient to the emperor.
During a coup, one could only depend on absolutely loyal private soldiers, which amounted to a mere eight hundred men.
As for the twelve guards, it was very possible that they couldn't be commanded on the day of the coup.
Moreover, it was difficult to bribe the members of the twelve guards, as they operated on rotational duties, and Lord Qin himself was not sure when the coup would begin. Bribing all of them would set too many targets and the leak of information could easily occur.
Therefore, Lord Qin aimed his efforts at the two guards he did not ostensibly control, namely the Left and Right Imperial Guards.
