Shikaku Nara would one day become the strategist of all Konoha, and he was someone Uchiha Yi had long had his eye on. It hadn't been convenient for Yi to get too close to Shikaku and the others before. They were all aligned with the Hokage, but Yi was still an Uchiha. Now that Hiruzen Sarutobi was making the introductions, his intentions were clear: he was paving the way for Yi and for Ino-Shika-Cho.
As far back as the Warring States Period, the three lesser clans of Ino-Shika-Cho had followed the Sarutobi Clan. The Sarutobi Clan had to witness the formation of each new Ino-Shika-Cho trio.
Hiruzen Sarutobi himself had witnessed this generation's formation. In a sense, it wouldn't be a stretch for Shikaku Nara to call him his teacher.
Since Hiruzen intended for Yi to become the future Hokage, it was only natural to bring him into contact with Ino-Shika-Cho.
Shikaku Nara was still young, and his strength was far from the highest in Konoha, but his intelligence ranked among the village's best. While he was young, he could be placed at Yi's side and become a trusted right hand.
Strength alone wasn't enough. Governing Konoha well required capable people. Yi couldn't exactly use his Sharingan to control everyone and make them work in perfect order, could he?
The One Country, One Village system had been established largely because there weren't enough capable ninja. Most ninja couldn't even read. How were they supposed to govern an entire region?
At the thought, Hiruzen Sarutobi drew a sharp breath. The Ninja Academy had greatly reduced illiteracy. Some of its classes taught academic subjects with little bearing on combat strength. He hadn't thought much of them before, but now he wondered: had his ruthless teacher been preparing all along to get rid