Hello, I'm a complete beginner in this field and I just use my bicycle to commute. My rear wheel got punctured and I need to inspect the inner tube. I removed the tire and the inner tube from the rim but it seems that I need to completely remove the wheel from the bike otherwise I can't proceed with the inspection. I tried using a wrench but I can't get the two main bolts to turn even a millimeter. I tried removing some screws first and I also disconnected the rear brake but that didn't seem to help. The mechanism circled in red reads as follows: "Lubrication is forbidden. Conduct an inspection every year where you bought the bicycle". I don't think it has anything to do with my problem but it makes me think that I'm not supposed to do this myself but I'm in Japan and going to the repairer is troublesome for a series of reasons so I don't have a choice. Also, the chain is protected by a metal cover, and overall removing the rear wheel seems such a hassle. I searched on YouTube but all the bicycles shown in the videos were different and removing the rear wheel seemed easier. I read the manual in Japanese and I also searched the web but I don't even know how to point out what kind of bicycle I have. It's obvious to me that it is just a bicycle for commuting and nothing like a mountain bike or the like. It was cheap and it's a nice bicycle but it has a load of cranky trash on the rear part that is making me regret not having bought a slimmer and plainer mountain bike. Maybe I'm not rotating the bolts with enough strength but that's all I can do unless I buy a longer wrench to add momentum. Do you have anything to suggest?