No kitchen can be imagined without a knife. This is the main tool that should always be sharp. How to sharpen a knife, if there are no special tools, read in details.
This can be done using porcelain dishes. There is a solid white stripe on the bottom of the back of the dish. It is necessary to quickly run a knife over it several times and rinse it with water.
An ordinary nail file also makes the situation worse. You need to put the file on a hard surface and run the blade of the knife over the file, repeat the procedure several times.
Find a smooth stone. Take the knife and run it over the stone several times. Or take two stones, wedge a knife blade between them, and force the knife through. After that, rinse the knife with water.