t dawn, one quiet Sunday morning in 1941, a fleet of approximately 400 Japanese aircraft launched a bold and fierce attack on the American naval base stationed in Pearl Harbor, prompting the US government to step into World War II.

The bridge of a Japanese aircraft carrier

© nationalinterest.org

By 1942, the expansion of the Japanese Empire in South East Asia had reached its peak. In less than 10 years, the Japanese Imperial Army controlled the great majority of the Pacific Ocean, and its naval force was on par with some of the most modern fleets on earth. The tactical efficiency and superiority of the Japanese forces in South East Asia came to an end when the mighty military and industrial power represented by the USA started reconquering strategic locations in the Pacific. The war finally ended in September 1945 with the surrender of Japan, putting an end to six years of atrocities, war crimes and suffering across the globe. As terrible and tragic as this period may be, it is also fascinating for historians and collectors on many levels. All over the world, households and families have a story to tell and share about this era; stories of suffering but sometimes, also, of love, fellowship, friendship or bravery. Frequently, these stories are retained in physical objects like letters, notebooks, military equipment and medals. And also in watches.

US soldiers observing an allied bombardment - note the wristwatches

© Histomil.com

World War II tremendously accelerated the development of all kinds of mechanical equipment, including planes, boats, telecommunications and navigation devices, and also watches. Each military force, whether based on land, in the air or at sea, needed timepieces. Watches were essential to navigate a plane, coordinate troops and attacks, time artillery shelling and so on.

A multitude of stories surround soldiers’ watches. When it comes to specific models, we can mention the “dirty dozen” family, the Majetek, the B-Uhr, the Tutima, the Radiomir Panerai, the split-second Universal Genève Cairelli and so on.

Longines “Majetek” supplied to the Czech Airforce

© Longines

Military-issue watches of both Allied and German troops have become famous in the vintage world. But what about Japanese timepieces?

In 1877, the battle of Shiroyama led to the total collapse of the last Samurai uprising against the central government, ultimately forcing the so-called “old” Japan and its traditions to enter an era of mass industrialisation and liberalism. During the Meiji period, industries flourished across the country, and Japanese entrepreneurs adopted Western technologies when the country started importing large quantities of goods. While the first watch ever produced in Japan dates back to 1879, it was not until Kintaro Hattori created Seikosha Co. Ltd in 1892 that Japanese watchmaking became a reality. By 1913 the company was issuing wristlet watches for Imperial army officers under the name “Laurel”.

Laurel - the first watch produced by Seiko

© www.seikowatches.com

By 1938, with the economy and industry largely influenced by war, Seikosha production rose to 1.2 million units per year. Looking at pictures of WWII Japanese soldiers it’s pretty obvious that watches were definitely less common than in other military forces, and were mostly worn by officers or specific tactical groups. At that time, Seikosha was the only company capable of producing large quantities of watches, but as raw materials became scarce, the army prioritised the manufacture of on-board instruments for tanks, planes and boats. Contributing to the rarity of materials was the fact that the government couldn’t ask their Axis allies to supply them with equipment, as Japan was isolated on the Pacific front.

Seikosha factory in 1935

However, while provision of timepieces dwindled towards the end of the conflict, the early days of the war were different. Initially, the Imperial army ordered large numbers of simple watches for the different armed forces, namely the ground troops, the navy and the air force (the Air Force wasn’t a true specific branch of the Japanese army, but pilots were still equipped differently from other ordinary soldiers). The specifications were mostly similar: manually wound calibre, small second, 24-hour dial with Arabic numerals and a chrome case. However, according to their allocation to a particular force, they supposedly had either an anchor (navy), a star (army) or a cherry blossom (air force). Finally, the Air Force model generally featured radium hands and dial for better visibility during night flights.

The three different versions of Seikosha military watches

© www.tapatalk.com

Little information is available on these watches, and some say that at a certain point in the war, the army stopped ordering them, and soldiers or their families had to buy them with their own money.

Another dial variant

© www.thewatchsite.com

Nonetheless, one other Japanese watch from the same era has raised more awareness among collectors. Originally named Tensoku, this 48mm watch was made for the naval pilots of the Japanese Imperial Army. At first glance, the dimensions, the crown and the overall shape of the watch are reminiscent of some timepieces worn by German pilots, for example the B-Uhr. However, the Tensoku seems to have been entirely designed and manufactured by Seikosha.

The Seikosha Tensoku

© www.watchuseek.com

The calibres were initially derived from well-executed and carefully finished 19L pocket watch movements, but were later downgraded to more basic models. When we look at the specifications, they are clearly correlated to the needs of the pilots. First of all, the size, at 48mm: the watch was meant to be easily readable and needed to be worn over the jacket or trousers (some pilots liked to attach their watch to their thigh) of the aviators. Secondly, the 12, 3, 6 and 9 indexes, as well as the top of each hand, were coated in radium, allowing for a better visibility during night operations. The big pumpkin crown was also designed with practicality in mind, as the watch was intended to be operated while wearing heavy-duty gloves. Finally, the bidirectional rotating bezel was also a crucial feature for pilots, to measure the elapsed time between targets.

Seikosha Tensoku caliber and caseback

© www.lesrhabilleurs.com

As steel was rare, and needed for other essential military equipment (planes, boats, tanks) the Tensoku cases were made out of nickel-coated material, a less durable material over time.

Again , information about these watches is scarce. We are not sure how many were made, or to whom exactly they were distributed. We know that very few pilots actually wore them, as most Japanese aviators used regular pocket watches during missions.

Japanese pilots wearing their pocket watch around their neck

© Getty Images

In fact, if you look at the famous Mitsubishi A6M fighter plane, also known as “Zero”, the cockpit had a dedicated aperture for a small pocket watch/chronograph that could be easily mounted or detached by the pilot himself. Some of them actually attached these pocket watches to a cord and wore them around their necks.

The Zero cockpit featuring a small aperture to fix a pocket watch chronograph similar to this one

As the situation of the Japanese Army became critical, resources were diverted to the units that needed them the most. The army made some desperate decisions. In their mind, American progress towards the Japanese mainland had to be stopped at all cost. It meant nearly 4000 young Japanese pilots committing the ultimate sacrifice for their Emperor, giving their lives in suicide attacks on the US fleet. Poorly trained and badly equipped, those young pilots launched stripped-down versions of the Mitsubishi A6M plane equipped with large bombs into US warships and aircraft carriers. Nineteen per cent of them reached their targets.

Given this terrible context, the planes were lightened, navigation systems were simplified (sometimes completely removed), and heavy bombs were attached to the chassis. The army tried to spare the most useful equipment for the plane, but the pilots were also asked to wear the strict minimum, as they had no intention of returning. So, while the Tensoku timepiece is morbidly nicknamed the “Kamikaze” watch, in actual fact it would not have been part of the usual gear of suicide pilots.

Japanese pilot - note the pocket watch around his neck

This rather horrendous tactic only delayed the inevitable victory of the American forces by a few months, and took the lives of young Japanese soldiers, frequently teenagers.

In parallel, the massive and sometimes questionable bombing of the Japanese archipelago, its infrastructures and the civilian population, put an end to the Pacific conflict and to World War II itself. In the process, most of Japan’s industries, including the Seiko factories, were totally wiped out.

Nevertheless, as it has demonstrated several times over the course of its history, Japan was able to look forward, and made a rapid and impressive recovery.

Fast forward a few years, and Japan watchmaking was rebuilding itself, and was already starting to snap at the heels of the mighty Swiss watch industry, itself untouched by war.

Left: Tokyo in 1945 after heavy bombing - Right: Tokyo in 1960