Don't respond to my post if you can't used your brain.No one is talking about the Sharingan here so I don't even know why you're bringing that up. The Sharingan doesn't make you smarter...
Shikamaru can form strategies, but he needs time to do it. Itachi on the other hand has been able to make plans in the midst of battle and carry them out while in combat.
Shikamaru is more of the behind the scenes tactician - like what Shikaku has been doing for the alliance.
Itachi is more of the type to use his smarts in actual battle
Someone was talking about the sharingan and that person is me.I brought it up to show how Itachi sharingan gives him an strategic advantage in battle compare to someone like Shikamaru.Saying something as stupid and pointless as "The Sharingan doesn't make you smarter" only makes me wonder about your mental state.It's obvious the sharingan doesn't make you smarter, but the sharingan does provides information, which in battle is nearly the same as being smarter.Knowing where you opponent is going to move before he moves and knowing what type of jutsu he going to use before he uses it would make any shinobis ability to plan in battle easy.Itachi relives heavily on the sharingan to give him information within battles while Shikamaru uses only his brain to figure out his opponents abilities and devise a strategy to defeat them.The Sharingan's second-most prominent ability grants the user an incredible clarity of perception, allowing them to easily recognise genjutsu and different forms of chakra, though not to the same extent as the Byakugan. This also allows the user to pick up on subtle details, enabling them to read lip movements[4] or mimic something like pencil movements.[5] As the Sharingan evolves, gaining more tomoe seals, this ability extends to being able to track fast-moving objects before finally giving some amount of predictive capabilities to the user, allowing them to see the image of an attacker’s next move from the slightest muscle tension in their body and counterattack or dodge without any wasted movement.
As for shikimaru needing time to plan strategies.Good thing he has the ability to stop his opponents movements.
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Of course this isn't as fast as Itachi, but Shikimaru doesn't have a sharingan.