If our expectation of advantage be tempered in this way, we may
succeed in accomplishing the essential part of our schemes.
信, according to Tu Mu, is equivalent to 申, and 務可信也 is
paraphrased by Chang Yü as 可以伸己之事. Tu Mu goes on to say: “If
we wish to wrest an advantage from the enemy, we must not fix our
minds on that alone, but allow for the possibility of the enemy
also doing some harm to us, and let this enter as a factor into
our calculations.”