日本在台湾附近的偏远西南群岛推动地下掩体建设，目标提供约两周的避难能力。核心数据包括：宫古岛预定使用地下停车场容纳约500人，计划最早于2027年度后完工；与台湾相距约110公里的与那国町将在町公所下方设置可容纳约200人的掩体。此举与日本在2022年安全战略中提出的西南地区疏散设施需求一致，并反映天候、人力不足与特殊需求居民支援不足等现实风险。

日本目前指定的临时疏散地点超过58,000处，纸面容量约为人口的140%，但地下设施不足4,000处，容纳能力低于全人口的5%。此结构性差距突显日本地下避难能力的量化不足，并与政府备置远距飞弹以提高威慑效果的政策形成对照。近期宫古岛等地进行机场疏散演练，凸显撤离策略仍以早期移转至九州等大岛为主。

南韩形成鲜明对比，拥有超过17,000处地下避难所，按每人0.8平方公尺计算，可提供超过三倍人口的空间；首尔即有约3,000处，部分地铁站备有瓶装水、LED照明与收音机，可维持一定时间的停留能力。相较之下，日本的地下掩体配置明显稀薄，强调其在潜在冲突情境下的量化劣势。

Japan is advancing underground bunker construction on remote southwestern islands near Taiwan, aiming to provide roughly two weeks of refuge. Key figures include a Miyakojima plan to shelter about 500 people in an underground parking facility, with completion expected in fiscal 2027 or later, and a Yonaguni bunker for about 200 people located roughly 110 km from Taiwan. These measures align with Japan’s 2022 security strategy calling for evacuation facilities in the southwest and reflect risks from weather, manpower shortages, and limited support for residents with special needs.

Japan has designated more than 58,000 temporary evacuation sites, with paper capacity at about 140% of the population, yet fewer than 4,000 are underground, offering space for under 5% of residents. This structural shortfall underscores a quantitative deficiency in underground protection and contrasts with Japan’s deployment of standoff missiles to strengthen deterrence. Recent airport evacuation drills on Miyakojima reveal that early relocation to Kyushu and other larger islands remains the principal strategy.

South Korea presents a sharp contrast, possessing over 17,000 underground shelters that can accommodate more than triple its population using an allocation of 0.8 square meter per person; Seoul alone has about 3,000 such sites. Some subway stations contain supplies such as bottled water, LED lights, and radios, enabling sustained sheltering. Relative to this, Japan’s underground capacity remains limited, highlighting a numerical disadvantage in potential conflict scenarios.