Question: Which castle is located near the royal mausoleums of the Ryukyu Kingdom on an island that has an estimated population of 1,518 ?

text: List of Cultural Properties of Japan - structures (Okinawa)
National Cultural Properties
As of 1 September 2017 , twenty-three Important Cultural Properties with forty-one component structures have been designated , being of national significance . [ 2 ] [ 3 ] [ 4 ]
This list is of the Cultural Properties of Japan designated in the category of structures (建造物, kenzōbutsu) for the Prefecture of Okinawa.
Property Date Municipality Comments Ref
Ieudun Tomb 伊江御殿 墓 Ieudun baka 1687 Naha turtle-back tomb of the Ie line , descendants of the seventh son of Shō Sei , fourth king of the Second Shō Dynasty [ 1 ]
Sonohyan-utaki Stone Gate 園比屋武御嶽石門 Sonohyan-utaki sekimon 1519 Naha heavily damaged during the war and restored to its previous form in 1957 ; part of the Prefectural Historic Site and of the UNESCO World Heritage Site Gusuku Sites and Related Properties of the Kingdom of Ryukyu [ 2 ]
Chunnaagaa 喜友名泉 Chunnaagaa 1751-1829 Ginowan stone castellum aquae or fountain [ 3 ]
Former Enkaku-ji Hōjō Bridge 旧 円覚寺 放生橋 kyū-Engakuji Hōjō-bashi 1498 Naha Enkaku-ji was founded by Shō Shin in 1492 ; all its wooden buildings were destroyed during the war ; the ornately carved bridge suffered minor damage and has since been restored ; its carvings are a Prefectural Cultural Property [ 4 ]
Miyaradunchi 旧宮良殿内 kyū-Miyaradunchi 1751-1829 Ishigaki residence of a senior Pechin ; the gardens are a Place of Scenic Beauty [ 5 ]
Former Sōgen-ji First Gate and Stone Wall 旧崇元寺第一門及び石牆 kyū-Sōgenji daiichimon oyobi sekishō before 1527 Naha Sōgenji , said to have been founded in 1470 , was destroyed during the war ; the gate was restored in 1952 [ 6 ]
Former Nakazato Magiri Warehouse Overseer 's Stone Walls 旧仲里間切蔵元石牆 kyū-Nakazato magiri kuramoto sekishō 1716-1735 Kumejima the wooden buildings are lost [ 7 ]
Former Yonaguni Family Residence 旧与那国家住宅 kyū-Yonaguni-ke jūtaku 1913 Taketomi part of the Taketomi Preservation District for Groups of Traditional Buildings [ 8 ]
Former Waukei Family Tomb 旧和宇慶家墓 kyū-Waukei-ke haka 1601-1700 Ishigaki combines a roofed cave burial chamber with a walled courtyard [ 9 ]
Tamaudun 玉御殿 Tamaudun 1688 Izena designation comprises two components : the burial chamber and stone wall [ 10 ] [ 11 ]
Tamaudun 玉陵 Tamaudun 1501 Naha designation comprises five components : the central chamber for temporary burial prior to washing the bones and final entombment , east chamber for the entombment of kings and queens , west chamber for the entombment of other members of the royal family , and inner and outer stone walls ; also an Historic Site and part of the UNESCO World Heritage Site Gusuku Sites and Related Properties of the Kingdom of Ryukyu [ 12 ] [ 13 ] [ 14 ] [ 15 ] [ 16 ]
Gongen-dō 権現堂 Gongendō 1786 Ishigaki designation comprises two components : the shinden and haiden ; first constructed in 1614 , destroyed by the 1771 Great Yaeyama Tsunami , and rebuilt the following decade [ 17 ] [ 18 ]
Takara Family Residence 高良家住宅 Takara-ke jūtaku 1868-1911 Zamami boatman 's house on Geruma Island [ 19 ]
Uezu Family Residence 上江洲家住宅 Uezu-ke jūtaku 1754 Kumejima designation comprises two components : the main building and anteroom [ 20 ] [ 21 ]
Aragaki Family Residence 新垣家住宅 Aragaki-ke jūtaku 1801-1911 Naha designation comprises four components : the nineteenth-century main building and workshop , and the 1911 annex and climbing kiln ; a potter 's house ( tsuboya-yaki ( 壺屋焼 ) ) [ 22 ] [ 23 ] [ 24 ] [ 25 ]
Sesoko Toteikun 瀬底土帝君 Sesoko tōteīkun late Edo period Motobu on Sesokojima ( 瀬底島 ) ; complex includes honden , haiden , garden , stone walls , hearth [ 26 ]
Former Ōgimi Village Office Building 大宜味村役場旧庁舎 Ōgimi-son yakuba kyū-chōsha  Ōgimi  [ 27 ]
Nakamura Family Residence 中村家住宅 Nakamura-ke jūtaku late Edo to Meiji period Kitanakagusuku designation comprises five components : the main building ( late Edo to Meiji period ) , anteroom , annexe , storehouse , and pigpen or fuuru ( all Meiji period ) [ 28 ] [ 29 ] [ 30 ] [ 31 ] [ 32 ]
Nakandakari Riverside Facilities 仲村渠樋川 Nakandakari hiijaa 1912 Nanjō amenities include a fountain , retaining walls , pavements etc [ 33 ]
Tsukayama Distillery 津嘉山酒造所施設 Tsukayama shuzōsho shisetsu 1928 Nago awamori distillery ; designation comprises two components : the main building and distillery [ 34 ] [ 35 ]