The Art of War by active 6th century B.C. Sunzi

3. When he has penetrated into hostile territory, but to no great

distance, it is facile ground. [Li Ch’uan and Ho Shih say "because of the facility for retreating," and the other commentators give similar explanations. Tu Mu remarks: "When your army has crossed the border, you should burn your boats and bridges, in order to make it clear to everybody that you have no hankering after home."]