Born to be loved

A couple months ago <a href = "http://born2b-loved.blogspot.com/2017/01/cats-and-asthma.html">we freed our cats again into the living space of our home</a> with a delight. Since then our son HG grew and got more and more curious to interact with the cats. He even says nya-nya (ﾆｬｰﾆｬ, Japanese onomatopoeia for cats meowing (=^・^=)) and calls the name of one of our cats, Nobi. For some reason he resists calling the other girl cat's name and instead calls her Nobi too, but hopefully he's learning and just not about confident to pronounce her name Tuna. So we decided in the same link above that we want to keep our master bedroom where HG sleeps at night free from cats, for the sake of his health particularly for his respiratory issue that he's been suffering. We've been simply keeping the door shut all day. For the first two months, it worked. But now Nobi, our mischievous young fur-ball, found a way to hang to the door knob and open the door, whic