本文以大阪商船株式會社在1924年至1943年間發行的雜誌《海》為研究對象，探討以航海為媒介的旅行知識，如何參與近代日本的海洋想像與殖民地觀光視野的建構。本文揭示《海》的雙重話語運作，「誡」與「界」互為條件，前者為旅人確立了抵達他者之域的現代主體姿態，後者則提供了據此姿態前往的外地風土。筆者進一步分析，刊物建立了現代旅行規範的「誡」，將「乘船即文明」的思維內化為讀者大眾的日常意識，形塑具有中產階級消費品味的現代旅人；此外，以尋找「真臺灣」為名的「界」，指涉透過東臺灣的原真浪漫、農村田野的地方色彩、現代治理下的樂土形象三種並行路徑，劃定文明與未開之間的觀看界線，使外地風土成為現代旅人確認自身文明優越感的鏡像空間。

This paper examines The Sea (Umi), a magazine published by the Osaka Shōsen Kaisha between 1924 and 1943, exploring how maritime travel knowledge participated in the construction of modern Japan’s oceanic imagination and its colonial tourist gaze. Drawing on the analytical framework of “The Commandment / Boundary of Civilization,” this article reveals the dual discursive operations at work in The Sea. The “Commandment” and the “Boundary” are mutually constitutive: the former established the modern subject position of the modern traveler approaching the domain of the Other, while the latter provided the colonial landscape toward which that subject directed its gaze. The article further argues that the magazine’s “Commandment” constructed a set of modern travel norms that internalized the ideology of “to voyage by ship is to be civilized” into the everyday consciousness of its readership, cultivating a modern traveler defined by middle-class consumer sensibilities. Meanwhile, the “Boundary,” operating under the rubric of “Discovering the Real Taiwan,” traced three parallel paths — the primitivist romance of eastern Taiwan, the local color of rural and pastoral landscapes, and the image of a livable paradise shaped by modern colonial governance — thereby demarcating the line of vision between the civilized and the uncivilized, and rendering colonial landscapes into mirror spaces through which the modern traveler confirmed their own sense of civilizational superiority.