Okay.Last Queastion,when the seal is placed on a kunai and thrown and it hits a summoning for example does the seal activate upon contact? Also can the enemy counter by simply not using a jutsu but just taking it off?
Well you are able to place the seal on other objects so you dont have to do it by hand.You are able to render summonings useless and also stop edo's when formed.The bad points would be that it requires contact with the thing you want to seal and also the thing you want to seal has to be big so it's easier to tag them.Also only works against edo's and summonings.
If it hits, yes, it activates upon contact. The enemy can counter it, as nothing is instant, but it makes them vulnerable. Also, it's not smart as it's easier to deflect kunais than to "pull it off".
Good, I like those (dis)advantages! Good job

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( Chakra Haisui Fūin no Jutsu ) – Chakra Suppression Seal Technique
Rank: B
Type: Supplementary
Range: Short
Chakra cost: 20
Damage points: N/A
Description: The user places this seal on the forehead of a Jinchuuriki influenced by the powers of a Bijuu, to forcibly cause the Bijuu's powers to recede. The Jinchuuriki becomes exhausted after this happens.
Note: This can only restrict Jinchuuriki in their Incomplete form, not when they completely transform into the Bijuu.
Now, this is only useful against a jinchuuriki. The problem is the short-range again. I doubt you'll ever really user it, but it has its uses I guess. Place it on their forhead and it will strip them of their powers!