Kai Tak Aerodrome Part 4 – War Time Operations
Tymon Mellor: On the 12 October 1938, two divisions of Japanese troops landed in Bias Bay (Daya Bay), not to attack Hong Kong, but heading for Canton (Guangzhou). The event was witnessed by a reporter from the China Mail who was being flown in a Hornet Moth belonging to the Far East Flying Training School at Kai Tak. Canton quickly fell and mopping up operations continued along the frontier until the end of that year. The Japanese troops were under clear instructions to respect the frontier until the 8 December, 1941, the day after Pearl Harbour when the Japanese invasion of Hong Kong began. Under the new administration, Kai Tak was to be transformed from a grass aerodrome into an airport designed to be the centre of air communications for the new empire.
With the Japanese occupation of southern China in 1938, it was clear that Hong Kong was at risk. The British were listening to Japanese communications and deciphered the code of the Japanese Navy in 1935, followed by the code of the Japanese Foreign Ministry[i]. However, with only limited staff they were not able to assess all the Japanese communications. In mid-1941 the Japanese realised their communications had been compromised and changed their codes.
Recognising the possible threat, the territory had to prepare for war.
The RAF prepared a Site Plan for Kai Tak identifying their facilities and future development, the drawing ‘Plan 441’[ii] was classified as ‘Secret’ and was maintained from February 1938 to October 1941. In the centre of the aerodrome, the plan identifies three areas of experimental runway trials and includes an outline of a future runway, 550m long and 45m wide. The trials were:
- 1934 Road Oil – A.P.CO, road oil being an asphalt product used to seal and provide a low-cost road surfacing;
- 1935 Bitumuls, a bituminous product for road construction; and
- 1936 Tarmac, a surfacing material consisting of crushed stone, sand and bitumen
There is no record of any further development of this runway configuration. The trials highlighted the desire to provide a permanent runway on the site but it would seem there was not the will or the funding to complete the task.
In 1935 the Air Ministry decided that an additional aerodrome was required for the defence of Hong Kong[iii]. A site at Pat Heung was chosen to be the base of the Fleet Air Arm leaving the RAF at Kai Tak. The new facility would become Sek Kong Airfield.
Not content with two aerodromes, by August 1936 the Air Ministry identified the need to acquire additional land for a third aerodrome, and a site at Ha Tsuen was identified[iv]. The concern from London was how to get the Hong Kong Government to provide the necessary land, free of change. Development of the Ha Tsuen site would not start until after the defeat of the Japanese when it would become known as Ping Shan.
In 1939 a government appointed committee recommended a new three runway arrangement and so technical studies for the scheme were undertaken. The proposal required extensive reclamation, possibly up to 8 million m3 of material and 3km of new sea wall, a major undertaking and something that would have taken many years to complete. The plans were abandoned with the impending war.
With the introduction of the Hawker Hurricane and Supermarine Spitfire fighter aircraft into the RAF in 1937 and 1938 respectfully, new requirements were demanded of the airfields. In a report drafted in October 1941, the Wing Commander stated, “Fighters cannot operate from here [Kai Tak] at present owing to small size [of airfield]”[v]. The aerodrome with the northern extension provided a runway of 730m with a marine approach, or 1,600m approaching south-east/north-west. A permanent runway was required and six schemes were identified with runway lengths varying from 1,050 to 1,600m and differing approach angles. With 64% of the wind being from the east or west, runways on that bearing were preferred. The east-west option B, C, D and E required extensive demolition of private buildings while the north-south option F required land acquisition and extensive filling.
The preferred scheme was Option A on a north-west south-east bearing, and providing a 1,460m runway with good approach. It had the advantage that there were no external interfaces so reducing the construction time, although it did require the dismantling of the RAF hangar on the east side of the aerodrome. The plan was approved and a contract was let to Fook Lee & Co to dismantle the hangar. It was always intended that the hangar would be re-erected so the steelwork was carefully marked and components crated for their future use. The materials were then stored adjacent to the Air Ministry Works Office at the eastern end of the RAF reserve[vi]. The proposed runway site was surveyed in October 1941 in advance of work commencing using direct labour working for the Air Ministry. The runway would be formed from granite blocks surface with a bitumen topping, the exact nature being finalised once the rate of bitumen supply could be established, but it was hoped that the works would be completed within three months.
Due to the sudden Japanese invasion on the 8 December 1941, none of the work was undertaken and Fook Lee would not be paid for the dismantling work until 1947[vii].
In addition to a new Kai Tak runway, satellite landing grounds were identified at Prince Edward Road east of the KCRC railway bridge and on the east side of the northern section of Waterloo Road respectively. The military was determining the necessary work to be undertaken to make these suitable for their aircraft when the invasion commenced.
The materials from the dismantled eastern hangar were surprisingly still in situ at the end of the war but upon re-occupation, the RAF sold the metal for scrap. During the occupation, the Japanese took great care to recycle all scrap metal from demolished properties, and so it is not clear why the hangar steelwork did not meet such a fate, unless it was planned to be re-erected at some future date.
The Japanese had a long running strategy known as ‘nashinron’ or ‘advancing southward’. Initially, this was interpreted as a marine trading strategy, the goal being to establish free-trade partners, but by the 1930s with the international isolation of Japan and with a shortage of natural resources, the strategy diverged to advocate military expansion. The Japanese planned to establish the Greater East Asia Co-Prosperity Sphere whose central concept stressed the importance of expelling the former colonisers and of cooperation among Asian nationals.
To achieve these goals Japan needed resources, particularly the oil in the Dutch East Indies (Indonesia) and the British Malaya (Malaysia). Thus, ‘The Imperial Navy Military Plans’ of 1938 stipulates that when attacking the United Kingdom, Japan should first raid their strategically important bases, including Hong Kong, Borneo, Malaya and Singapore[viii]. As a symbol of the British empire, attacking Hong Kong would send a strong signal that Japan intended to establish the Greater East Asia Co-Prosperity Sphere with the hope that other Asian countries would collaborate and free themselves of western colonisation.
A more immediate reason for occupying Hong Kong was to stop the flow of goods and money supporting the Nationalists (Kuomintang) lead by Chang Kai-shek in China. Hong Kong played a key part in smuggling arms and commodities supplied by the Allied Nations and the United States. Stopping the supply would hasten the end of the fighting with the Chinese Nationalist forces.
The Hong Kong Strategy
Following the occupation of Hong Kong, the Japanese went about implementing three key tasks and aspirations. Firstly, they needed to fortify the city and establish a large military base, secondly, they would use the city as a political base to continue their subversive activities against the Nationalist government, and finally, to transform the territory in to an economic and political base serving the southern part of the Japanese Empire[ix].
The deep-water port, dockyards and the Kowloon Canton Railway made the territory an ideal logistics hub to support the ongoing expansion of the Greater East Asia Co-Prosperity Sphere.
To achieve this goal, the occupying authorities would promptly rebuild the damage from the fighting, restore the basic infrastructure, and re-establish commercial activities to regain its pre-war trading status. To achieve this goal, it was necessary to establish cooperation from the Chinese population. This would be achieved by co-opting the Chinese elite and business men to assist in the governance of the territory, “using Chinese to govern Chinese”[x].
The Japanese were early adopters of flying and established the first training school in 1918[xi] and developed its own aircraft industry. Commercial aviation began in 1922 when the Japan Air Transport Institute established several domestic routes. By 1928 the Japanese government established the national carrier, the Japan Air Transport Corporation, and the first airport at Haneda in Tokyo opened in August 1931. By the 1930s, three companies were established to manufacture the latest in aircraft technology, Nakajima Aircraft Company, Kawasaki Aircraft Industries and Mitsubishi Aircraft. Spurred on by the Imperial Japanese Army and Imperial Japanese Navy, these three companies would come to develop fighting machines for the military.
Japan Air Transport Corporation was heavily subsidised by the Japanese government and had a close relationship with the Japanese military. In 1936 they adopted the Douglas DC-2 aircraft for their most popular routes, and in 1938 they carried nearly 70,000 passengers, representing 2.6% of the world’s passenger traffic[xii].
Given the important role Hong Kong was to play in the new Japanese empire and its ideal location as an aviation hub for south east Asia, it may be no surprise that unlike all the other cities occupied by the Japanese army, it was decided to upgrade Kai Tak aerodrome. Hong Kong as an air communications hub had the advantage over Canton with good seaplane access, military facilities and security. As reported by the Hong Kong News in 1943, Mr Takamatsu, head of government communications stated “it is the intention of the Government to make Hong Kong a centre of land, sea and air communications”[xiii].
Spies Amongst Us
Hong Kong was always an international port, with various national representatives keeping an eye on each other. Prior to the occupation, the Japanese started to compile the ‘Hong Kong Military Gazette’ in 1926, a secret dossier on the territory’s geography, garrison, transport, population and other related information[xiv]. Other studies were undertaken, with a focus on military infrastructure and defence. The Gazette was updated in 1938 and again in 1939 with information provided by local supporters and the Italian Consul. In August 1939, the Japanese produced a 1:25,000 scale map of the territory showing the defensive positions and sites of interest.
Gathering information and data for the Gazette required a network of hundreds of Japanese spies recruited from residents in the colony, and many later revealed themselves in senior uniformed positions after the surrender, along with the anti-British Indians allied with the Japanese and also the gangs of Wang Ching Wei followers who were fifth columnists. No doubt some were employed incognito in lowly positions at RAF Kai Tak and at the civil hangar offices, and could have had access to the British plans for Kai Tak. These then could have been passed to the Japanese when the buildings were ransacked after the attack on the airfield in December 1941.
Designing an airfield requires contributions from several specialists including:
- understanding of the local topography requiring detailed maps of the proposed site and the approaches;
- the local weather requiring meteorological data; and
- the requirements of the aircraft that are to use the airfield.
At the time of the Japanese occupation the most common aircraft were the ‘flying boats’ and early twin engine passenger planes such as the DC-2, but it was becoming clear that land-based planes were the future and they were going to get larger and heavier requiring longer paved runways. This would be particularly important given the tropical weather and heavy rainstorms prevailing in Hong Kong.
Given the scale of the works required, it is likely that the initial design was undertaken before the invasion by Japan when all the necessary skills and expertise were available. The Hong Kong dossier would have provided all the necessary local information. The design had to address local wind patterns and drainage, with the provision of a new 3km nullah and extensions to the existing drainage system. It also had to address the earthworks necessary to create the enlarged platform, as well as the pavement layout and design for the new runways.
Given their extensive spy network, the Japanese should have been aware of the proposed three runway scheme developed in 1939. However, they did not adopt that scheme, preferring to extend the aerodrome north and west instead. This is probably due to the extensive reclamation required for the scheme. Reclamation requires specialist marine vessels and the sourcing of a large quantity of fill. Extending the aerodrome inland just required labour to excavate spoil and use as fill, and construct waterways, a more practical arrangement given the resources available.
The Japanese solution was to provide a two-runway arrangement requiring the aerodrome to be extended west and north increasing the area from 77 hectares to 178 hectares. Each runway was around 1,370m long, with the main runway on bearing 13/31 being 100m wide, and the secondary runway on bearing 07/25 being 65m wide. Both were designed with a concrete pavement and a turning bay at the ends. The existing western hangar clashed with runway 07/25 and was to be removed and with a new hangar constructed to the north of aerodrome at Tai Hom.
Limited information is available about the construction works. However, the British Army Aid Group (BAAG) provided regular reports on the developments at Kai Tak and as such, it is possible to piece together the Japanese methodology.
On a Thursday morning in September 1942, the Chief of Staff held a ground breaking ceremony for the aerodrome enlargement works[xv]. The report noted that 800 prisoners of war would be deployed from the 15 September, increasing to 1,600 by late September and by October around 4,000 workers would be toiling on the aerodrome to create one of the biggest airfield in the Far East.
The reality on the ground was slightly different. According to the BAAG, demolition of the buildings commenced in late June 1942 with tractors levelling the ground to the north of the site. Clearly, this was not going down well with the residents and in August, it was reported that the authorities were “doing everything possible to alleviate the hardships caused”[xvi]. Two model farm communities were established, one in the New Territories at Sheung Shui for 270 families and one at Kowloon Tong accommodating 250 families. Each family was compensated with 200 Yen and one catty (about 600g) of rice. Many were employed on the airfield enlargement works. By March 1943 the two farms had become “Model Villages” and the remaining 500 families moved there from the affected homes[xvii].
Following the end of the war and the return of the British administration, the “Airfield (Kai Tak) Extension and Reversion Ordinance” was passed in July 1948 to provide payment or alternative land as retrospective compensation for the loss of land and property. The estimated total compensation payable was around $5 million[xviii], but I have not been able to identify the final settlement.
In November 1942, a BAAG agent managed to copy the proposed plan for the airport, showing the scale of the works at hand. By the end of the year around 10,000 coolies and 800 prisoners of war were deployed to level the villages and form the airfield. Between 50 and 120 Japanese soldiers were based on the airfield living in the former RAF facilities. Throughout the expansion works, the aerodrome remained operational, and in 1942 the aerodrome typically serviced three flights a day increasing to around 10 by March 1943. In April 1943 daily commercial passenger flights resumed between Kai Tak and Canton but you needed to obtain a permit from the General Staff Office before purchasing the ‘MY30’ ticket.
In January 1943, security on the site was tightened and martial law introduced when it was discovered that a map of the works had been stolen. It was not clear who had stolen the map, but two men were arrested and no doubt given a severe sentence. Soon after, it was reported that a map of the works was offered to an agent in Macau but he turned it down as they had already acquired a copy[xix].
The original programme for aerodrome expansion works was six years, but by March 1943 with just 30% of the project completed, the programme was accelerated to complete the work within four years. The workforce was boosted to over 7,000 men, 1,000 women and up to 2,000 prisoners of war.
The extension of the aerodrome to the north would have required around 0.8 million m3 of fill to raise the paddy fields to the airfield level. This material was sourced from the demolition of the Po Kong village and hill, excavation for the nullah and from the surrounding hills. The adjacent Kowloon City was surrounded by a large stone wall made from granite slabs extended up the adjacent hillside. In August 1942, the Japanese army used the stones as the foundation for the runway. The prisoners of war had to remove the heavy stones from the city wall, transport them to Kai Tak, where they were placed in an excavation with a weak concrete bed to form the foundation of the runway[xx].
For the reclamation on the west side, the 45m high hill at Sung Wong Toi was used for the source of material. The feature known as Sacred Hill included the Sung Emperor’s Terrace, a small group of boulders where in the 13th century the boy Emperor, ﬂeeing the Mongol invaders, landed in Kowloon and took up temporary residence. To commemorate the event, the largest of the boulders was inscribed with Chinese characters, declaring it to be the Sung Emperor’s Terrace. Aware of the cultural sensitivity of the stone, the Japanese had the area exorcised on 9 January 1943. Fifty white-clad monks staged a three-day vigil to make the ghosts of the hill depart. This done, the hill was partially demolished to secure the material for the reclamation. The inscribed boulder was not damaged and after the war, the boulder with the inscription was cut out and erected in a park adjacent to the airport while the remains of the hill were cleared for a new runway.
In late April 1943, the BAAG reported that a concrete runway, 30m wide extending from the western hangar to the barracks on the east side, had been constructed. At 600m long, this would have been suitable for small planes. The layout was designed to connect to the existing western hangar used to house the aeroplanes.
By the summer of 1943, the new platform was substantially complete and work had commenced on the drainage provisions. Nullah number 1 was to be covered over and three new covered nullahs were constructed through the new formation. The design was probably based on the original arrangement utilising concrete foundation piles and a twin 225mm concrete arch roof spanning the 7.6m wide nullah.
Around the perimeter of the new airfield a new nullah was constructed, ranging from 7.6m wide on the east to 15.2m wide on the west, the nullah drained all the surrounding land. The construction detail required a stone facing to create the channel. Looking at contemporary aerial photos, two quarries are visible on the north-west and north-east sides of the works. These are likely to have been the source for much of the granite.
The nullah is currently being refurbished by CEDD and DSD to revitalise the area, and let’s hope they respect the heritage and the memory of the people that suffered during its construction.
The western hangar was used by the Japanese during April 1943 when two fighter aircraft were identified. However, by March 1944 the hangar had been dismantled and partially re-erected at Tai Hom. The original hangar was 36.5m wide and 76m long but the new hangar was only 36.5m wide and 28.6m long. This is probably due to the structural arrangement of the western hangar, with a side door along much of its length, only the end three bays formed a stable portal, giving a maximum building length of 28.6m.
By September 1944, the two new runways were complete and a small control building had been erected on the remains of Po Kong hill. The Governor issued an order on the 7 September 1944 to cease all construction activities on the aerodrome.
Being a high value target, the Japanese took action to protect the aerodrome. Anti-aircraft guns were installed at key positions and in April 1945, earth revetments were constructed all over the airfield to hide and protect the planes.
To protect the Tai Hom hangar, a bund was constructed around the structure and a pillbox was constructed to the east to protect the structure from an attack from the sea and Clear Water Bay Road.
At a territory wide level, the Japanese built a radar station on Tai Mo Shan to provide early warning of any incoming air raids.
Prisoner of War Labour
In 1975, Tony Weller was interviewed about his time as a prisoner of war (POW) working on Kai Tak aerodrome. He had been captured at Cape D’Aguilar on the day of the surrender of Hong Kong on Christmas day 1941. From there he was taken to the Sham Shui Po POW camp and was assigned to Kai Tak as a labourer. Initially it was just cutting the grass airstrip and moving loads, but in July 1942 things started to change. The whole camp would be woken before dawn to take a requisitioned Star Ferry round to Kai Tak. They then spent the day demolishing Po Kong Hill, taking the spoil down the hill in four-wheel bogies to tip in to the fields and raise the ground level. The work was very hard and by early 1943 the POWs started laying the first concrete for the runway. The quality was very poor with an excessive sand to cement ratio resulting in the concrete frequently falling apart. It was hoped that this would hinder rather than help Japanese planes.
At the War Crimes Court in December 1946, further evidence was provided on the operation[xxi]. The Japanese demanded that 800 men worked on the airfield each day, and on occasions unfit men had to be used to meet the quota. POWs were housed at North Point and Sham Shui Po, but food and blankets were in short supply with only a small tin of rice a day for dinner. The POWs comprised Britons, Canadians and Hong Kong volunteers, and they would take breakfast at 4:30am before roll call at 6:30am and then onto the ferries. Work was from 8am to 6pm with a one-hour break for lunch at noon. They would arrive back in the camp at 8pm for their evening meal consumed in the dark, wash and in bed by 10pm.
The work was probably not much better for the Chinese working on the airfield, but at least they were paid.
Tai Hom Hangar
In the summer of 2013, the corroding skeletal remains of the Tai Hom hangar were exposed, scanned, dismantled, treated, and placed into a temporary store located below the Kwun Tong Bypass. The structure had been identified as being made from the components of the western civilian hangar dismantled by the Japanese during the war. The basis for this assessment went back to November 1951 when the Director of Civil Aviation, who had been closely involved with the construction of both hangars, provided some much-needed advice. At the time, the Hong Kong government and the RAF were in dispute over ownership of the structure and over the payment of rent. The doors on the Tai Hom hangar matched the side doors from the original western hangar and the building had a travelling hoist, which was not present in the eastern RAF hangar. Not exactly conclusive proof, but a check on the height of the structure may have been more definitive as the western hangar was 1.5m taller than the eastern structure. However, it was sufficient to resolve ownership, and the RAF had to pay rent.
Along with the hangar, the adjacent Japanese pillbox was also removed from the site to make way for the new Diamond Hill Station of the Tuen Ma Line.
In 2020, funding was agreed from Legco for a new Water Feature Park adjacent to Diamond Hill Station, and this new park would be used to exhibit the Japanese pillbox and the pre-war hangar. Construction of the park is in progress and the pillbox has recently been delivered into position [March 2023].
With the end of the war, the Hong Kong government inherited a two runway airfield, but a growing new aviation industry required longer runways and improved facilities. How will the territory respond to this new challenge?
Thanks to Kazuto Miyahira Thesis The Japanese Occupation of Hong Kong The Strategic Importance of Hong Kong and the Details of the Japanese Military Rule provide much of the background for this article
The Chinese University of Hong Kong Library for The Hongkong News
BAGG Reports in Industrial History Hong Kong
[i] Eastern Fortress, A Military History of Hong Kong. 1840-1970, Kwong Chi Man and Tsoi Yiu Lun, 2004
[ii] Hong Kong Kai Tak Aerodrome Extension: Works Policy, National Archive AIR2/1851, Oct 1941
[iii] Air Ministry to Secretary of State for the Colonies, CO129/551/8 31 Oct 1935
[iv] Air Ministry to Secretary of State for the Colonies, CO129/551/9 15 Aug 1936
[v] Report upon the fighter defence of Hong Kong and the establishment of a flying boat base in Hongkong Island, AIR 2/1851, 29 Oct 1941
[vi] File Note by Director Civil Aviation, 27 Nov 1951, PRO 156/1/2990A
[vii] Pre-Occupation Claims, AIR 2/6497 1 April 1947
[viii] Yu Nakazawa 中澤佑 (from the Imperial Navy), “Showa jusan’nendo kaigun nendo sakusen keikaku,” 昭和十୕ᖺ度海軍ᖺ度作戦計画 (The Imperial Navy’s Military Plans, 1938), in Shiryoshu kaigun nendo sakusen keikaku 資料㞟 海軍ᖺ度作戦計画 (A Collection of Primary Sources: The Imperial Navy’s Annual Military Plans), ed. Boeicho boeikenkyujo senshibu (Tokyo: Asakumo shinbunsha, 1986), 37, 61.
[ix] Takashi Sakai 酒井隆, “Honkon koryakugo niokeru gunsei jisshi ni kansuru ken,” 香港攻略後
ニケࣝ軍政實ニ關ࣝࢫ件 (About the Japanese Military Rule over Hong Kong after the
Successful Invasion), accessed via Japan Center for Historical Records on April 16, 2016,
[x] Snow, The Fall of Hong Kong, 95; Kobayashi and Shibata, Nihon Gunseika, 61
[xiii] Bright Future for H.K., To Be Centre of Communications, The Hongkong News, 20 Jan 1943
[xiv] Eastern Fortress, A Military History of Hong Kong. 1840-1970, Kwong Chi Man and Tsoi Yiu Lun, 2004
[xv] Work On Kai Tak Airfield, Breaking The Sod Ceremony, The Hongkong News, 11 Sep 1942
[xvi] Compensation To Kai Tak Residents, The Hongkong News, 19 Aug 1942
[xvii] Model Village Opened in Sheung Shui, New Homes for Over 1,000, The Hongkong News 4 Mar 1943
[xviii] HKRS46-1-3_Part 2
[xix] Kai Tak Airport – BAGG reports 1942-1944, plus other HK Landing Strips, https://industrialhistoryhk.org/kai-tak-airport-baag-reports-1942-1944-plus-landing-strips/
[xx] Research Report on the Use of Stones from the Kowloon Walled City in the Kai Tak Nullah, 15 Jul 2018
[xxi] POW Enlarged Kai Tak Site, Hundreds Employed to Remove Hill, SCMP 15 Dec 1946
This article was first posted on 18th March 2023.
Related Indhhk articles:
- Kai Tak Aerodrome Part 1 – Kai Tack Bund
- Kai Tak Aerodrome Part 2 – Construction
- Kai Tak Aerodrome Part 3 – The Roaring Thirties