Isekai manga where a guy gets reincarnated as a nobleman's son and invents Othello

Question

I'm looking for an iseaki manga about this guy who gets reincarnated as a nobleman's son and they live in the Countryside. He ends up being really happy about it because he wants to live a quiet slow life. I think he was also secretly really strong but didn't want people to find out. I think he could use earth magic? He made a hideout/house in the forest and a traveling adventure went into his hideout thinking that it was a rest stop for travelers. The adventurer is this really strong guys who ends up being really grateful to the boy for feeding him.

He also had an older sister who is really bossy but good at sword fighting and would regularly beat him up in sword training practice and a younger brother who was sweet but weak. He ends up getting bored so he invents othello which ends up becoming really popular, which draws the attention of some important nobles which are friends of his father. He also was teaching the chef how to make sweets with sugar in it, but they had to be really careful because his mom and sister could smell out sugar whenever it was mentioned.

Answer 1

I believe this is Tensei Shite Inaka de Slowlife wo Okuritai, also known as, I want a slow life in the countryside after reincarnation

The main character is reincarnated as Alfred Slowlet, a nobleman's son. As mentioned in the title, they live in the countryside and he wants to live a slow life. He has spacial magic, which he uses to move things around. Early on he goes to his hideout and is practicing by moving rocks, twigs and other things around. He can also use elemental magic, including earth. Later he finds a traveling adventurer sleeping in his hideout and feeds the adventurer.

He has an older sister who is good at sword fighting, and beats him up during sword practice. He has a kind older brother who is younger than the sister, and much weaker.

He teaches the chef how to make various food, including sweets. Early on the when Alfred mentions sugar, his mother and one of the maids appear saying they thought they heard someone mention sugar.

He also makes othello, though version i linked uses the name Reversi. He teaches it to the townsfolk and they end up holding a tournament during a festival. There he meets and faces nobles who are friends with his father.