Season 4 of Haikyuu begins approximately at chapter 290. But keep in mind that there might be some variations depending on different translations or editions.
The ending of season 4 of Haikyuu in the manga is at a point where a major plot development occurs. It's a bit complex to pinpoint exactly, but it's related to a key match or event in the story.
It ends at a specific chapter that focuses on a crucial match and character development. But I can't recall the exact chapter number off the top of my head.
The start of Haikyuu Season 4 in the manga is approximately at chapter 290. This might not be exact as sometimes there are differences in how the content is presented and divided between the two mediums.
Celebrating Years Season 2, episode 13 was the 13th episode of Celebrating Years Season 2. The play told the story of a young man with a mysterious background, Fan Xian. He had experienced the trials and tempering of his family, the martial world, and the court. He upheld justice and kindness and began a new journey in life. In this episode, the news of Fan Xian using the name of investigating corruption to target the Second Prince's faction spread like wildfire in the Jingdou officialdom. At the same time, the murderer of Baoyue Brothel was finally caught. The battle between Fan Xian and the Second Prince was becoming increasingly white-hot. Baoyue Brothel became a tool for the Second Prince to check and balance Fan Xian. The Second Prince tried to pull Fan Xian into the water and cause the people to boil. Fan Xian walked the path of being close to the people. What he valued more was the will of the people. Fan Xian asked his subordinate Deng Zi Yue to spread the word that the manager of Baoyue Brothel was Yuan Meng, and Yuan Meng was an old lover of the Second Prince's subordinate, Li Hongcheng. This was the reason why the Second Prince was framing Fan Xian. Fan Xian and the Second Prince displayed two countermeasures. Fan Xian walked the path of being close to the people. What he valued more was the will of the people. Therefore, Fan Xian asked Deng Zi Yue to spread the word that the manager of Baoyue Brothel was Yuan Meng, and Yuan Meng was an old lover of the Second Prince's subordinate, Li Hongcheng. Anyone with a brain would think that the Second Prince was framing Fan Xian. As for the details of the specific plot, one had to watch the 13th episode of the drama to understand.