[UPDATED] 二戰時期的日軍防空塔
WWII Japanese Pillboxes on Formosa

Site A (Source： Google)

[Update]: Many thanks to Michael Carl, who provided information on the pillboxes on CCK Air Base, and to Mark Spearman for the info on the pillboxes on Tainan and Kangshan Air Bases. This post has been updated accordingly.

上面這張照片裡的子彈型水泥建築是日軍在二次大戰期間建造的，位於台中水湳機場的東邊。有人稱之為防空機槍塔，有人稱為砲塔，也有人把它叫做碉堡。最近我在日軍檔案裡找到一份文件，把這種防禦工事稱做「防空塔」，並且詳細繪出了內部配置與部署的方式。下面第一張圖顯示這種防空塔的水泥牆厚達80公分，頂部有個架設防空機槍（或機砲）的凹槽（MA），其下有機槍的射口（MG），再下是戰防砲之類大口徑武器的射口（A～AB），器材與彈藥則存放在戰防砲底部的空間，之下還有通往地底的垂直坑道。
The concrete pillbox in the top photo is just off the east perimeter of the now-abandoned Taichung Shuinan Airport. There are quite a few pillboxes like this one on Taiwan, which was built by the Japanese army during WWII. I had been wondering what they were for and what were inside until I found the drawings below in the Japanese archive. The first drawing shows the concrete wall is 80-cm thick. There is a cavity on the top for mounting an anti-aircraft cannon (MA). Below the cannon emplacement, there are embrasures for machine guns (MG). The ground level has larger embrasures for field guns (A and AB). (But how was the field gun moved inside the pillbox? Was the gun “built in”?) Parts and ammunitions are stored below the field gun. Beneath the storage is a vertical tunnel.

Source： Japan Center for Asian Historical Records アジア歴史資料センター

第二張圖顯示防空塔之間是以地下坑道相連結，有些地下的部分可做為部隊棲息之處，最讓人驚奇的是還有更深入地下的空間，只是圖上並沒有說明這地底空間的用途。
The second drawing depicts that the pillboxes are inter-connected by underground tunnels. These tunnels lead to an underground rest area. Deeper down there is a bullet-shape hollow, whose function is not clear.

Source： Japan Center for Asian Historical Records アジア歴史資料センター

第三張圖說明每三座防空塔構成一組，相互支援火力，兩兩之間的距離在1000到2000公尺左右。圖的右上方還繪出長方形或方形的碉堡。
Three inter-connected pillboxes form an interlocking defense system providing covering fire to each other, as shown in the third drawing below. Each pillobox is spaced 1000 to 2000 meters apart from the other. The drawing also depicts several rectangular or square pillboxes, which are not as tall.

Source： Japan Center for Asian Historical Records アジア歴史資料センター

下面這張水湳防空塔的衛星照片清楚顯示了頂部的凹洞，與日軍文件的結構圖相符。
The following overhead satellite image of the Shuinan pillbox reveals the anti-aircraft emplacement on its top:

Source： Google

這類防空塔多半位於機場的四周。到目前為止，我在台中地區發現了三座，但理論上應該更多，因為日治時期大台中地區的機場至少有四座，只是有些防空塔可能在國民政府接受後被拆毀。以下我把能在Google Earth街景照片上看到的防空塔一一列出，或許還有一些是我所不知的。下面第一張照片裡的防空塔位於台中都會公園內，跟最上方照片裡的防空塔屬於同樣的形式。
These pillboxes are often placed around airfields. So far I have found three in the greater Taichung area. There could have been more since there used to be four airfields here, but it is almost impossible to know how many have been torn down. In the following, I list those pillboxes on Taiwan which can be seen on Google Earth‘s Street Views. The one in the image below is located in Taichung Metropolitan Park. It is of the same type as in the top photo.

Site B (Source： Google)

目前仍存在的防空塔似乎有幾種不同的形式，下面這個位於大肚區遊園路旁的防空塔看起來就跟前面的兩座不一樣。
This type of pillbox has several variations. The one below, which is not as tall and does not have the field gun embrasures, is found by Youyuan Road in Dadu District.

Site C (Source： Google)

[2012/12/19 Update]:
網友Michael Carl留言後，我找到這張2006年在清泉崗基地拍到的照片，但並非他提到的那一座，所以清泉崗至少有兩座：
Prompted by Michael Carl’s comment, I found in my photo archive the following image that I took on CCK Air Base in 2006. The pillbox in the image is a different one than that described by Michael.

Site D

我在2010年到現場看過下面這座位於彰化縣福興鄉的防空塔，有人在戰防砲的射口加上了窗戶。這座防空塔與Google Earth上看不清楚下下圖的另一座共同防衛著以往彰化飛行場的西北與東南隅。
I visited the next one in Fuxing Township, Changhua County, in 2010. Somebody has put a window on the field gun embrasure. This pillbox and the other one , which can only be partially seen on Street Views and is not shown here shown below it were built to guard the former Changhua Airdrome.

Site F (Source： Google)

Site G

[2012/12/22 Update]:
網友Mark Spearman提供我以下兩座位於台南基地內的防空塔座標：
Mark Spearman emailed me after seeing my post and gave the coordinates of the two pillboxes in Tainan Air Base, whose photos are shown below.

Site H (Source： Google)

Site I (Source： Google)

[2012/12/22 Update]:
Mark Spearman另外指出下面兩座位於岡山基地外北側的防空塔座標：
Mark Spearman also showed me the two pillboxes to the north of Kangshan Air Base:

Site J (Source： Google)

Site K (Source： Google)

以下這座位於高雄市彌陀區（我還是比較喜歡五都升格前的名稱）的台17線公路旁。論地理位置，應該也是防衛岡山飛行場。
The one in the next photo can be found along Route 17 in Mituo District, Kaohsiung City.

Site L (Source： Google)

下面位於屏東縣新埤鄉的這座防空塔，可能不是用於防禦機場，因為它距離潮州、潮州東、佳冬等三座飛行場都有一段。當地政府在周圍建了一座碉堡公園，算是待遇最好的防空塔。
The government of Xinpi Township, Pingtung County, has built a park around the pillbox below.

Site M (Source： Google)

聽說以下照片裡的防空塔曾出現在電影「海角七號」裡，只是我真的記不得有看過。它就位於屏東縣佳冬教會的隔壁，顯然是為了佳冬飛行場的防禦而建造的。
The one in the next photo, which is located in Jiadong Township, Pingtung County, is said to be featured in the hit movie Cape No. 7. But I did not notice it when I saw the movie.

Site N (Source： Google)

為了便於大家親臨現場踏查，我把我知道的防空塔位置標示在Google Maps上。首先是中台灣的部分：
In case you want to see these pillboxes in person, I have marked their exact locations in Google Maps and you may want to consult them. First are those in central Taiwan:

View 中台灣防空塔 Pillboxes in central Taiwan in a larger map

南台灣的部分如下：
Those in southern Taiwan:

View 南台灣防空塔 Pillboxes in southern Taiwan in a larger map