I would not recommend this build in ranked games because if u want to play an ap mid champ this is probably not the best option. If u wanna go support as janna this isnt the build you're looking for either. However. If u want to have fun in a normal game and surprise alot of other summoners this is just you're build.

The runes i selected in my build is only for damage. Not much more to say about them.

The items are selected so that you have alot of damage earlygame and then lategame you can go a little bit more support with more defensive items but still be able to flunk out alot of damage. Jannas E spell Eye of the Storm is very efficiant if you have alot of ability power and that is another reason for you to follow my build :)

I chose flash as a summoner spell since janna is a good chaser and can slow the enemies alot. therefore you should be able to flash forward to slow an enemie who is running. Of course it's also a great tool for escaping. Jannas ulti pushes back nearby enemies, and if you wanna be able to control you're ultimate much better u can flash and then use you're ultimate to maby get ur opponents beneath ur turret or into ur team. or just away from ur team. that can easily be done with the flash-ulti combo. The summoner spell Surge is very underrated in my opinion. its great for janna both earlygame and lategame. Her spell Eye of the Storm gives a friendly champion attack damage. And if you play Janna in mid lane you use it on yourself. therefore it's a great advantage to have some attack speed with that attack damage. and the ability power is also a very nice boost