The English on the box says, "Gokiburi Hoi-Hoi is a roach trap which has No. 1 quality in the world."
It's inevitable. Even when you don't see them, they are there. Every summer in Japan, roaches start skittering across the walls or floors of your living space. In our apartment, we generally only see one or two per year. I'm not sure if this is because there are so few or if they stay out of sight. Either way, viewing one often elicits an adrenaline rush and a quick run for a can of spray to douse them with.
My husband and I aren't very comfortable with killing anything, even creepy insect things, but there are two exceptions - roaches and mosquitoes. The latter seem to have a laser targeting system for my husband and wake him up at night when they bite him. In fact, the first night back from his trip to the U.S., he was awakened three times by mosquito bites from three different ones (who have since met their maker for their misdeeds). It's not exactly the best way to spend your first heavily jet-lagged night back home. Fortunately, while he was in the U.S., he ordered a mosquito net from Amazon and carried it back with him and I put it up for his second night back.
Unfortunately, you can't erect a barrier against incursions by roaches and be satisfied they won't find a way around them. They have no respect for your borders and can squeeze around nearly anything you put in their way. You have two options for attempting to keep roaches out of your home. The primary one is to make your environment less inviting. This is done by keeping things cold and clean. The latter is time-consuming but doable. The former is expensive and difficult in the Japanese summer.
I've read about other options for making roaches unhappy but I'm uncertain of their efficacy. One thing I have read is that roaches hate the smell of bay leaves so I scattered bay leaves around last summer after our second sighting. I didn't put any in the bathroom, however, and that's where one showed up today. It's also very likely that the leaves I put out last year have lost their scent through time and it's time to put out fresher ones. You can now pick up big bags of bay leaves cheaply at Costco for about 300 yen so it's not much of a financial risk to give this a try.
The second option is to destroy any roach that dares to cross your threshold. One of my husband's students clued him in on a product in Japan which can best be translated to "roach jelly". It's poison but it's not the same as a spray or one-trick poison. The way it works is the roaches sniff it out and then track it back to the wife and kids where it supposedly poisons the whole lot of them where they live. I put those out last year as well but they also have aged beyond utility (they tend to degrade through time and with moisture collection) and it's time for a fresh round.
The one thing I have not done in the past is set up roach traps (front of box pictured at the top of the post and the back above this paragraph). One of the reasons I've avoided traps is that I didn't think we had enough to make them worthwhile. I'm still not certain we have that many but I did finally conclude that if the trap catches one or two rather than us being shocked by seeing one crawling on the wall, they are worth the small investment.
The way these work is that the unsuspecting roach wanders around your house and gives everything a sniff. Suddenly, he thinks 'something sure smells good' and wanders in the direction of the enticing odor with the idea of finding himself a snack. When he gets there, he finds a cheery little yellow house with a red roof and cute pink shutters. There's even a friendly roach giving him a wave out one of the windows welcoming him inside. The roach moseys on in with a false sense of security only to find himself stuck. Once there, he starves to death.
You can see that, as someone who doesn't like to kill anything, this is a somewhat disturbing concept. I don't like how inhumane this process is. At least poison kills them relatively quickly. I'm also not incredibly comfortable with the idea that the traps attract the roaches. Though I doubt they come far and wide at the scent of beef and shrimp chemically reproduced on a piece of cardboard, I don't want to do anything to draw them inside. However, if I can't ward them off with bay leaves and the level of cleanliness that I can manage, I'd rather trap them than have them fly past my head when I get up in the middle of the night to go to the bathroom. Besides, last year I opened a drawer and a roach that was clinging to the bottom of the drawer fell directly on my foot. As far as I'm concerned, that was crossing the line. No more "Mr. Nice Guy".