The telephone as postwar infrastructure and kaidan device. The basic entry covers the contagious structure of Kashima Reiko's curse; this fuller explanation looks more closely at the medium that carries it: the telephone. In Japan, the spread of black rotary phones into ordinary households rose sharply in the postwar decades, from about 8 percent in 1965 to about 80 percent in 1975. It is unlikely to be a coincidence that a legend emerging in the 1970s chose the device of "a question coming by telephone." The anxiety of a new infrastructure entering the home became part of the legend's core machinery. Where prewar Aka Manto belongs to alleys and night roads, and Hanako-san of the 1980s belongs to the school toilet, Kashima Reiko is distinctive because she violates the postwar private space of the household telephone. From the 1990s onward, the setting expanded into text media such as email and LINE, keeping pace with the evolution of postwar communication infrastructure.

The structure of the "Where are your legs?" question. At the center of the Kashima Reiko legend is a question: "Does Kashima-san have legs?" "Where are her legs?" and similar variants. A wrong answer is fatal, but correct replies such as "Kamashi," "Kashima Reiko," "above the waist," or "from above the waist downward" are said to save the listener. Like Aka Manto's "red paper or blue paper" and Kokkuri-san's yes-or-no exchanges, this is a no-win question structure common in children's oral ghost stories. At the same time, it offers an escape route: correct knowledge can save you. Folklorist Noboru Miyata, in Yōkai no minzokugaku (Iwanami Shoten, 1985), argued that question-based children's kaidan satisfy a childhood desire for intellectual advantage, the feeling that those who know the answer survive.

The transformation of postwar social memory into ghost story. The theory that Kashima Reiko began with the "1948 Kakogawa American-soldier incident" has not been historically confirmed. Even so, it preserves in ghost-story form a social memory of sexual violence suffered by Japanese women under the U.S. occupation. Postwar U.S.-Japan relations, defeat, occupation, and the security order, left many experiences insufficiently spoken in official discourse. Such unspoken harm can settle into the underground layer of urban legend and surface in the 1970s as a supernatural presence. Folklorist Norio Murakami has discussed this mechanism of social memory turning into kaii, noting that experiences excluded from public memory can remain in the form of ghost stories and spirit possession. Kashima Reiko is a representative example.

Contagious curses in the internet age. Kashima Reiko's structure, in which hearing the story makes one part of the curse, became a foundation for the chain-mail culture, internet curses, and creepypasta of the 2000s and beyond. "Forward this email to X people or you will be cursed," "anyone who sees this URL will be cursed": these online curse formulas have their prototype in Kashima Reiko's instantly contagious oral kaidan. Internet-era kaidan such as Kunekune (2003) and Hasshaku-sama (2008) inherit the same device, turning the reader into a participant in the curse. Kashima Reiko therefore played an important mediating role between 1970s oral kaidan and 2000s internet horror.

The ecology of Teketeke and Kuchisake-onna. Postwar Japanese children's oral kaidan do not exist as isolated beings. They form an ecology of mutual reference, merger, and branching. Kuchisake-onna (1978), Kashima Reiko (late 1970s), and Teketeke (1980s) follow one another chronologically and share motifs: a damaged female body, a question structure, and a curse aimed at children. In Tōru Tsunemitsu's Gakkō no kaidan (Kodansha KK Bunko, 1990), these stories were gathered under the category of "school kaidan," helping establish them as a single folkloric genre worthy of study.

Dandadan and modern transmission. In Yukinobu Tatsu's Dandadan, serialized in Shueisha's Shonen Jump+ from 2021 and adapted for television anime in 2024, Kashima Reiko was reshaped as a major supernatural figure and became familiar again to Generation Z. The adaptation keeps the key elements of the source tradition, the missing lower body, the telephone, and the contagion of the curse, while recasting them in the character language of contemporary shonen manga. From children's oral legend in the postwar 1970s to manga and anime of the 2020s, Kashima Reiko has become a rare urban kaidan transmitted across nearly half a century.