I would like to know what makes a lawn mower into a mulching mower. Is
this as simple as removing the bag and let the grass clippings to fall
on the lawn? This is exactly what I have been doing for two years. But
I am not exactly sure if I am doing this right.

Actually, I have a feeling that I have been doing this wrong. The
reason is that the grass clippings are kind of long. I believe the
grass clippers are supposed to be much shorter if I used a mulching
mower. I am wondering what I can do to make my lawn mower to work
better for mulching. Is this as simple as replacing the stock blade
with a blade for mulching? Does the blade for mulching have a longer
cutting edge as compared with the stock blade? (My stock blade only
have 3" cutting edge in each end of the blade). Does the blade for
mulching have a different shape from a stock blade?

Thanks for any info in advance.

Jay Chan