In this fanfiction, Harry could have won by being more aggressive in his play. He may have sacrificed some of his less important pieces early on to gain an advantage in position. His ability to stay calm under pressure, which he learned from facing various dangerous situations in the wizarding world, might have also played a crucial role. He could have observed Sona's reactions to different moves and adjusted his strategy accordingly. For example, if Sona seemed hesitant when he moved a certain piece, he might have continued to target that area of the board.
I'm not sure specifically if there is a fanfiction with the exact premise of 'Harry Potter is a pro chess player'. But considering how fans love to reimagine characters in different scenarios, it's very likely. The world of Harry Potter has so many elements that can be tweaked in fanfiction. Chess is also a significant part of the wizarding world, so it would make sense for someone to write a story where Harry is a pro at it. You could also try reaching out to Harry Potter fanfiction communities on social media platforms to ask if they've come across such a story.
Yes, there might be some out there. However, it's important to note that the 'beating up' aspect should be in line with the overall themes of justice and equality in the Harry Potter universe. Some fanfictions might handle this concept well, showing Harry standing up against the unjust pureblood supremacy ideology in a way that stays true to his character.
One possible plotline could be that Harry discovers a new dark plot by pureblood supremacists to further marginalize non - pureblood wizards. He decides to take matters into his own hands and uses his magic to fight them off. Another could be that he is pushed to the limit by the constant discrimination from purebloods and finally snaps, leading to a showdown.
It can make Harry seem more hot - tempered. Instead of always being the patient hero, beating up Malfoy shows his impulsive side. He's not just the boy who waits for the right moment to fight Voldemort, but someone who can take immediate action when his friends or his own pride is at stake.
In this kind of fanfiction, Harry might have learned chess from a young age, perhaps from an unexpected source like a hidden wizard in the Muggle world. His chess skills could help him solve mysteries in the wizarding world. For example, he might find clues hidden in the moves of a magical chess set. He could also use his chess knowledge to outwit his enemies, like Voldemort's followers. His games could be epic battles, not just of strategy but also of magic, with pieces that come to life in more spectacular ways than in the regular wizarding chess we know from the books.
A common plot is that Malfoy spreads false rumors about Harry in the wizarding world. This causes problems for Harry, like making some students avoid him or look at him with suspicion. When Harry finds out that Malfoy is the source of these rumors, he gets angry and beats him up. There are also fanfictions where Malfoy tries to get Harry expelled from Hogwarts by framing him for something he didn't do. Harry, being the brave character he is, doesn't take this lying down and gives Malfoy a good thrashing.
There might be a fanfiction where Harry and Sona are students at Hogwarts at the same time. They could form an unlikely friendship and help each other with their studies. For example, Sona could be really good at potions and help Harry improve his skills in that area.
One common theme is growth. Harry often grows as a person or wizard after being 'beaten' by Snape. For example, he might learn from his mistakes or develop new skills.