Decluttering
It took three hours for me to organize my bookshelf in the living room. That means I have hundreds of more books in other bedrooms.
According to the KonMari method from the book named The Life-Time Changing Magic of Tiding Up, I must discard any items which are not bringing joy to me when I touch them.
Honestly, there are only a few books that bring joy. So I might have more work to do with the bookshelf in the living room.
Now I have more space on the bookshelf, so it can hold new books with no problem.