Ginny Weasley opened the Chamber under Tom Riddle's control; however, she only could open it because of Riddle's ability to speak Parseltongue.
After being slipped Tom Riddle's diary by Lucius Malfoy, Ginny began to write in it as Tom's spirit would slowly drain the life from her. In return, Tom compelled Ginny to open the chamber, cause mayhem around the school and then be the next victim to die after Myrtle.
Ginny Weasley was possessed by Tom Riddle's (Voldemort's) Horcurx at that time. Tom Riddle was indeed a Heir of Slytherin and a Parseltongue, so Ginny didn't run into any trouble opening the Chamber of Secrets. Unknowingly Ginny poured out her heart's desire on to the cursed diary.
Harry Potter and the Chamber of Secrets
During the climax of the story, it is revealed that she opened the Chamber of Secrets, and is attacking Muggle-born students while being possessed by Tom Riddle's old school diary. Lucius Malfoy had slipped the diary into Ginny's cauldron in Flourish and Blotts prior to the term.
In the second Harry Potter movie, we learn that Ginny was putting the blood writing on the walls, by Tom Riddle's order. Ginny opened the Chamber of Secrets by Tom Riddle's order as well. Though at the end of the movie, Ginny confesses. But she didn't tell her WHOLE story.
Neither of them is Slytherin's heir. Although, as Dumbledore says, Harry's ability to speak Parseltongue is a skill accidentally transferred by Slytherin's actual heir, Voldemort, when he tried to kill Harry as a baby. So perhaps this is one myth with a bit of truth to it.
Through this dialogue, Tom grew stronger and ultimately poured a little of his soul into Ginny, manipulating her to kill Hagrid's roosters and open the Chamber of Secrets.
SHE'S A PROFICIENT AND POWERFUL WITCH
J.K. Rowling has stated one of the reasons Ginny is gifted is due to the fact she was a seventh child and the first female Weasley born in generations, which ties into the superstition of the seventh daughter of a seventh daughter.
She didn't block it. She ducked, she dodged it, she moved her head or body to avoid it. No one has blocked the curse with a spell to do that.
She breaks up with Dean in Harry Potter and the Half-Blood Prince, finally winning the affection of the only boy she has ever loved, Harry. Unfortunately for Ginny, Harry ends their relationship to protect her from Voldemort at the end of Harry Potter and the Half-Blood Prince.
The unusual talent known as Parseltongue, which Harry possesses, is passed through a family bloodline. Given that many Dark wizards and witches, including Lord Voldemort, also possess this talent, it is regarded as a dark gift.
Ginny Weasley was able to speak Parseltongue while she was possessed by Tom Riddle's Diary, which enabled her to open the Chamber of Secrets.
In Harry's second year, Ginny Weasley re-opened the Chamber; however, it was not on her own that she did this. We find out in the last chapters of the book that Ginny was at the time enslaved by a "memory" of Tom Riddle. Ginny re-opens the chamber on six occasions that we are aware of.
The closer a writer became to the memory of Tom Riddle emotionally, the more power the diary would acquire over him or her. For example, Ginny poured her fears and desires into the diary, thus it was easy for Tom to possess her.
The first time we see her burn herself is in season 1, episode 2, when, after a particularly overwhelming day, Ginny turns off the light, closes her bedroom door, and takes a lighter to her inner thigh. Scars from past burns are clearly visible, as are angry welts from recent ones.
Harry is the Heir of Gryffindor (though his powers have been bound by his father when he was a baby), Neville is the Heir of Hufflepuff, Meghan (OFC, daughter of Sirius) is the Heir of Ravenclaw. Harry/Ginny, Ron/Hermione, Remus/Tonks.
To do this, they must first commit murder. Voldemort intentionally made six Horcruxes, but when he used Avada Kedavra on Harry, he unintentionally created a seventh Horcrux. Instead of dying, Lily's love for Harry created a counter 'curse' known as Sacrificial Protection and saved Harry.
The author explicitly states that both women were fighting to kill, despite Molly refraining from casting the Unforgivable curse Avada Kedavra. The result of the duel actually comes about as a result of nothing more than spectacular accuracy on Weasley's part.
Ginny and Hermione each have their own strengths. For Hermione, she's logical, book smart, and clever. Ginny is smart too, but in other ways. She's more kinesthetic and she's a gifted Quidditch player.
She gets to act like an ass and is rewarded for it: she hexes Zachariah Smith for no reason other then him “annoying her”. She can insult people but will tear into anyone who does it: she calls Luna “Looney” when she first introduced her to everyone but will jump anyone else who does it.
And because Harry misses his parents James and Lily Potter and battles Voldemort throughout the story, he feels that he has something to prove. All of these things combine to make Harry Potter more powerful than Ginny Weasley.
June 13, 1942: Tom Riddle murders Myrtle Warren (a.k.a. Moaning Myrtle) in the first-floor girls' bathroom at Hogwarts School of Witchcraft and Wizardry, sending a piece of his soul into his diary. It becomes his first Horcrux.
After being left alone in the Gaunt family hovel, Merope bewitched the Muggle boy she had a crush on, Tom Riddle.
However, Malfoy still possessed the diary and, in 1992, he planted it on Ginny Weasley, hoping to kill three birds with one stone by sabotaging Ginny's father, purging the school of muggle-borns, and eliminating an incriminating piece of dark artefact.