Despite the Mermaid saga being one of Rumiko Takahashi's lesser-known works, quite a few pieces of merchandise were made for it.
Telephone cards (telecards)
1993 Shonen Sunday Spring Special, 50 units. The kanji on this card say "Ningyo no Kizu" (Mermaid's Scar), but the images are from Mermaid's Gaze.
Ningyo no Mori (Mermaid Forest). Weekly Shonen Sunday, 50 units.
Ningyo no Mori. Victor/JVC, 50 units.
Ningyo no Kizu. Shonen Sunday Open Dai Zokan, 50 units.
Ningyo no Kizu. Promotional item. Victor/JVC, 50 units. The picture of this card was taken from a Yahoo Japan auction.
Ningyo no Mori. Shogakukan, 50 units. This telecard was part of a boxed 5-card set celebrating 100,000,000 copies sold of Rumiko Takahashi's comics. Each card came in its own small holder on which was printed the cover of the first tankoubon (volume) of their respective manga. The Mermaid saga card holder has a picture of the "Ningyo no Mori" wide edition.
Posters and chirashi (leaflets)
This small glossy poster features Towa and Mana from "Mermaid Forest" and it seems to be advertising the "Ningyo no Mori" wide manga version. I don't know how people got this poster, although it comes folded up, so I'm assuming it came inserted in some manga.
This small glossy poster features Mana from "Mermaid Forest" and it seems to be advertising the "Ningyo no Mori" wide manga version. Measures about 20 inches by 14.5 inches. I don't know how people got this poster, although it comes folded up, so I'm assuming it came inserted in some manga.
This glossy chirashi (leaflet) advertises the Mermaid Forest TV series that aired in Japan in 2004. Here are scans of the front and the back. Measures about 10 inches by 7 inches. I believe the small form in the bottom-left corner of the back is an order form for the limited-edition boxed DVD set.
This chirashi (leaflet) advertises the Mermaid Forest TV series that aired in Japan in 2004. Here are scans of the front and the back. Measures about 11.5 inches by 8.5 inches.
This large, glossy poster advertises the DVD box set of the Mermaid Forest TV series that aired in Japan in 2004. Measures about 28.5 inches by 20 inches. It is also advertising a limited-edition print of a picture of Towa and Mana that appeared on a previous poster. How you got this print, I don't know.
Doujinshi (fan-drawn comic books)
"Memory" by unknown artist. Regular doujinshi with various stories, including several 4-panel comic strips. 16 pages. Published February 2005.
"Koi suru sakana" by Jun Suzuki. Hentai (adult) doujinshi centering around Yuta and Mana. 24 pages. Published winter 2003. The actual cover does not have the black box on Mana's chest.
"Ningyo no Yume" (Mermaid's dream) by Herb Cake. Regular doujinshi centering around Yuta and Mana, with cameos by many of the other characters. This seems to be more comical in nature, and includes several 4-koma gag strips. 18 pages. Published Dec. 29, 2003.
"Natsu no owari" (The end of summer) by unknown artist. Regular doujinshi centering around Yuta and Mana, with artwork of some of the other characters that appeared in the manga series. Also includes several 4-koma gag strips. Comes with a doujin postcard of Yuta and Mana. 38 pages. Published Dec. 29, 1997.
Cels and other items
Original animation cel of Towa from "Mermaid Forest." Unknown position. The picture shown here is actually a cropped version of the original cel, which was up for auction at Yahoo Japan back in 2001. The full cel has Towa on the left side while the rest of the cel is blank. Here's a picture of the full cel with an artificial black background that I had added in Photoshop some time ago. I unfortunately don't have a copy of the original, unedited scan.
Original animation cel of Towa from "Mermaid Forest." Position B3. Sketch included.
Original animation cel from "Mermaid's Scar," featuring Mana. Position A8. Autographed by Rumiko Takahashi.
Script from Episode 5 ("Mermaid Forest," Part I) of the TV series. 38 pages. I don't know what the official industry term is. I don't know who owned this or who actually used it. This particular script also includes handwritten notes of sound effects and onscreen actions, such as when the scene pans up.
A sticker included with the first pressing of the CD single "Mizutamari," the ending theme to the Mermaid Forest TV series. Measures about 5.5 by 4.75 inches.
A sticker of the Mermaid Forest cover, measuring a little less than 3 inches by 5 inches. Part of the "Rumic World" Mini Photo Seal (sticker) Collection, released by Movic. The collection was sold in sealed packets (like the "blind boxes" that anime figures are often sold in), with one sticker per packet, and featured artwork from Takahashi's various series. There were a total of 40 stickers; only 1 was from the Mermaid series.
A standard-sized postcard measuring about 4 inches by 5.75 inches. Comes as part of a set of 5; however, I got my set secondhand so I don't know if there are other postcards in the series. (The other postcards in the set have Takahashi artwork for some of her lesser-known stories: "Fire Tripper," "The Laughing Target," "One-Pound Gospel," and "Wasted Minds.") I don't know how people got these postcards or who released them.