Okay so you're coming to Japan and you've been told that you need to bring this and this because they don't have it in Japan or it's too expensive to purchase there. Well, they were telling you half-truths.
1. Yes they do have deodorants but NOT antiperspirants (although there are a few if you look hard enough).
2. Neckties are expensive, NOT! I've found decent ones for just 3-400 yen! so just bring a few and get the rest here.
3. For women...They in fact DO have tampons and pads (are they the same things? they have the little thing you put in and the pads). So don't fret, you can get them here.
4. Toothpaste...if you have a preference then yeah bring it. Otherwise there is only ONE toothpaste with flouride (which you will need since they don't put it in the water system or anywhere in Japan). They have Aquafresh so if you don't mind that brand then save the weight.
5. Mouthwash. Well there are a lot here now but you have to look a bit for Listerine. But I think it's worth the hunt. Don Quixote (not spelled that way though >_>; ) is a major super center so you can get tons of stuff cheap and Listerine for cheap too! The only place I buy it.
6. Hot peppers! Although it's hard to come by, you can usually find pepper plants at a home super center. I found Habanero, "chili bombs", jalapeño, korean spicy chilies. But if you don't grow them yourself, you're out of luck. You can freeze them after harvesting time and add it to food as you go during the winter months. But if you have a sun room, you can continue growing them throughout the winter. I did that with the habanero and it continued until Feb when I decided to cut it down to get it ready for the next season.
Tip: as long as you don't let a ripe chili drop naturally, you can continue thru the next season. But if it does drop then the plant automatically stops producing and you need to use the seed to start over from scratch. So harvest when it just turns ripe and it will continue on.
What they don't have but should...
1. Flaming hot cheetos, and lots of it!
2. Affordable cheese...it's too damn expensive here!
3. Taco Bell outside of the US bases!!! argh! I want taco bell so bad >_<;
4. a lot of other things that will make this list too long!