Shingai jutsu!

Name: Wall of Benevolence
Rank: A
Element: Earth
Description: This jutsu simply enables Shingai to create a large 30 foot in length wall which surrounds the user and the enemy completely, and locks them in. The top is open, but is a mere 200 feet high, making it extremely difficult to get out. If the opponent tries to jump onto the walls to escape, the wall will immediately close in on the opponents body part, crushing it completely. This also renders the entire area in shadows, making it difficult to see. This wall is infused with a large portion of Shingai's chakra, enhancing its defensive structure by the tens, fortifying it by a small amount.

This is a little too powerful to be a A-Rank technique, more like S-Rank. If you want to keep it A-Rank, then lower the strenght of the jutsu.

Reduced.

Make it lower, its still a little to high.

Disapproved.

Too OP.