Why is my cheap kitchen knife so sharp?

I had a blue handle IKEA kitchen knife for 5 years. I cook every day and my kitchen knife was only 4 years at least. While i run standard maintenance on all my kitchen knives that I am confused how can this knife cheap (which comes in a range of $ 10 or less) be clearer then my other knives, I bought later. Although I have not compared to other brands like, etc. World, but my cheap knife is even better than my mid-range Japanese made knives and kitchen knife any other I've used. Slices of carrot, without effort! Does anyone more similar priced plastic handled knife from IKEA? Is it too sharp?

Tang dynasty Chinese swords- the ancestor of Japanese swords