Guard Point is the talented transformation of Tony Tony Chopper, doctor of the Straw Hat Pirates in the One Piece series. This form of defense comes from his many transformations that he has learned with his skill in the powers of the Hito Hito no Mi Devil Fruit. In Japanese, it is called "Fur Strengthening"; literally, "Guard Point".
When Chopper uses the Guard Point, his fur grows out exponentially, covering his whole body with a thick, fluffy barrier. From this form, Chopper's defensive abilities are immensely improved; hence, he is able to survive powerful impacts and ensure his and others' safety. Visually, the result of Guard Point is somewhat comical: Chopper becomes, in all intents and purposes, a huge, round, furry ball—more akin to a stuffed animal than to any kind of steadfast protector.
The strength of Guard Point lies in the power to absorb and disperse impact force. The fur works like some form of cushion that significantly reduces the damage Chopper would have taken without it; the Guardian Point has the defensive ability to keep him on his feet, fighting against different enemies along the series. Its ability to protect has been very useful in most of the battles that have been carried out during the series.
As far as combat utility is concerned, Guard Point is mostly defensive in nature. Relative to most of the transformations Chopper has, increasing his offense, Guard Point is particularly for protection. This is what makes it of vital essence, kept in Chopper's arsenal, especially in situations where either the Straw Hat Pirates need to bear heavy attacks or civilians must be protected.
With the fame of Guard Point among fans, it has made its way into several merchandise and collectibles related to One Piece. Chopper's Guard Point appearance has been noted in trading cards, such as those used with the One Piece Trading Card Game. Such as a trading card from Starter Deck 1: Straw Hat Crew, showing Chopper in his full Guard Point glory — complete with his great defensive abilities coming into play.
What is interesting, once again, is the fact that in the One Piece Trading Card Game, Guard Point is represented as an Event card, not a Character card. This card is used to permit a player to raise the power by 3000 points of one's leader or character cards during a battle. The implementation of this game mechanic is very similar to its defensive properties in the series: the ability of Chopper to take damage without flinching results in an increase in power for the characters in the game.
The trading card game did register the Guard Point card as a Counter type Event, meaning that it only plays during the counter step of a turn. This additionally increases its versatility as far as strategic use is concerned, as players would need to gauge the most opportune time to use Guard Point judiciously. This game design choice, however, comes much closer to representing the tactical considerations Chopper has to make when deciding to use Guard Point in actual combat situations within the One Piece narrative.
The Guard Point card has seen a number of printings, some in the Super Pre-Release Starter Deck 1, and others in the regular Starter Deck 1: Straw Hat Crew. When a card is reprinted in so many sets this simply further reinforces that Guard Point is a pivotal part of the nature and fighting style of Chopper.
In the larger context of Chopper's overall character arc, Guard Point is representative of his development not just as a fighter, but as a protector. It symbolizes his role as the crew's doctor, focusing on defense and protection for his friends above gaining offensive power. Since it fits so well with Chopper's core character traits, Guard Point is among the more important changes in his repertoire.
As the One Piece story went on, Chopper's control over his Guard Point has been, much like the other ones, polished. In that case, the form initially required a Rumble Ball for him to take this form, but over time, he has been able to take this form at will, meaning a higher level of mastery of Devil Fruit powers. The first and foremost being character development in Chopper and his rising importance to the Straw Hat Pirates in terms of combat capabilities.