After Nawaki's party arrived at the Western Ninja Village, he immediately ordered the 200,000-strong Shinobi Army to take up defensive positions in the West Forest District. He also arranged for the border towns to prepare for evacuation. To avoid alerting the enemy, he sent out no scouts and did not even deploy Tianxing Fortress.
Clearly, Nawaki intended to lure the enemy deep into the West Forest District and wipe out the Sunagakure Shinobi Army there. He trusted the Anbu branch to send him accurate intelligence in time.
Sure enough, late that night Nawaki received a secret letter from the Anbu in Sunagakure. Since Sunagakure was preparing to launch a surprise attack on the Land of Fire, it had to ready supplies and mobilize its forces. It had therefore lifted its total lockdown, allowing the Anbu branch to reestablish contact with the outside world.
The intelligence Nawaki received was comprehensive. Sunagakure would send a 100,000-strong Shinobi Army to attack the West Forest District at dawn the next day. Even its marching route and objectives were laid out in detail!
With that information, Nawaki immediately adjusted his army's defenses and issued a series of targeted orders to ensure his plan succeeded. Some units were to retreat rather than win, pulling back as soon as they encountered the enemy. Civilians in certain towns had to abandon all their possessions and supplies and evacuate at once. Other units were to remain at designated positions, forbidden from attacking without orders and required to conceal themselves from the enemy.
The Konoha Shinobi Army found Nawaki's strange orders hard to understand. But given the Skywalker's prestige, every unit carried them out faithfully, without the slightest disobedience.
Dawn came quickly. Just as the intelligence had predicted, Sunagakure's 100,000 troops launched their surprise attack on the West Forest border