The 4-bar box and the 3-bar box, both with identical soap and the same price. The bars used to come wrapped in paper, but were changed to plastic, unfortunately.
There's an episode of "3rd Rock From the Sun" where Sally, the alien who has been stuck in a female body during their mission to earth, is informed by her three cohorts who have conveniently been placed in male bodies, that she doesn't smell as good as other females on earth.
In response to this, she goes to a department store and attempts to buy soap. The woman at the counter keeps asking her if she's tried a variety of designer skin care products. After each query about moisturizer, exfoliating solution, etc, Sally, asks, "is it soap?" With growing impatience, she keeps saying she just wants soap, but the saleswoman wants to sell her some expensive, luxury skin care products. Eventually, the clerk tosses a bunch of samples into a shopping bag and Sally ends up comically addicted to skin products she can't afford to buy.
This scene reminds me of my quest in Japan for soap because, like Sally, I just want soap. I don't want perfume. I don't want moisturizer. I don't want pretty colors. I just want something that lathers up well, cleans well, and has as little scent as possible. I fail to see the point of using soap which coats you in some sort of lingering perfume-like smell. The soap is supposed to get you clean so you don't smell at all. Having perfume applied by your soap seems to imply that you've got an odor that needs to be covered up. If you're a perfume fan, on the other hand, you're likely going to do better than whatever scent the soap leaves on you by applying actual perfume to your body.
Avoiding the perfume in soap goes a bit further for me than merely not wanting to smell like nothing rather than some warped approximation of a flower (though I'm guessing that sounds ironic coming from a talking orchid). In small enclosed rooms in the summer, any sort of fragrance will fill the room. I've had students with modest levels of scent who have left my living room tinged with their soap or perfume for hours after the lesson is over. If a person is very sensitive to a scent, the experience of being trapped in a 4.5 mat room (about 9' x 9') with that person can be unpleasant. Also, my husband has an intense dislike for perfume and doesn't want to use any soap with a scent so the quest for just soap is a righteous cause for both of us.
There is a lot of very nice Japanese soap, but the majority of it is scented. Even the standard bar of white Kao soap, which is quite a creamy and luxurious soap for a low price, is a bit too heavily scented for our tastes. For years, my husband and I bought Ivory soap that was imported from the U.S. for about 100 yen a bar (about a dollar). At some point in the not so distant past though, the price went up and our income went down. Instead of 4 bars costing $4, they now cost $6 or more, and it just seemed like too big a luxury on our 1.3 incomes.
After Ivory scaled beyond our budget, I started sampling Japanese soap again. Fortunately, you can usually sniff a package and know if it has too much perfume in it as they are usually far from hermetically sealed. At one point, I bought a box of extremely cheap (4 bars for about a dollar) soap and found the closest thing we've come to Japanese scent-free soap. The second phase of the test though would be how it lathered up in hard water. Fortunately, it does adequately in that regard.
The soap is not made in Japan, which likely explains why it's so cheap though clearly it is made for the Japanese market when you look at the box design. Some of what it says is that it's made with milk and that it's gentle. It's made in Malaysia and the company name appears to be "Nid". However, about a year ago, the box size changed and now it's 3 bars for a dollar (about 98 yen) most of the time. Occasionally, a box with 4 bars will show up again. It's still a bargain in either size. There is a tiny little logo on the box which is hard to read. I did a little searching and found that they make several varieties of soap which are all priced the same, but none of those varieties is sold in my area.
In fact, finding this soap at all requires me to shop at a drug store. Markets rarely carry it. I'm guessing this is because the margin for profit on such items is razor thin (or it's a loss leader). In general, personal care goods like toilet paper, soap, etc. are always appreciably cheaper at drug stores than markets in Tokyo and, at 33 yen (30 cents) a bar, this is cheap soap.
If you just want soap, and you're trying to save money, I recommend using this particular brand. It's certainly no worse than the more expensive brands in terms of effectiveness and fills the bill if you just want to be clean, but not perfumed. However, I don't think I'm translating the characters right as "plant soap", but the first two characters can be read as "plant" and the second two as "soap". Besides, there are all these leaves on the box design so it's not such an absurd conclusion that the first word might be "plant". ;-)