As part of the German Military Mission initiated in 1913, numerous German officers and sergeants were deployed to serve in the Ottoman army. Despite their service alongside Turkish forces in land, naval, and air units, there are unfortunately few written records of their experiences in Türkiye. Memoirs penned by officers such as Otto Liman von Sanders, Friedrich Kreß von Kressenstein, Hans von Kiesling, Erich Serno, and Hans-Joachim Buddecke, who spent extended periods in Türkiye, serve as invaluable sources frequently referenced in Turkish historiography of World War I.

It is also possible to encounter German officers who served as observers in Türkiye for short periods. Among them was Oswald Boelcke (1891-1916), known for his 'Dicta Boelcke' theory, which consists of eight principles, and his distinguished service as a pilot in the German army, where he shot down 40 enemy planes before his death. Although his visit lasted only two weeks, traces of Boelcke's time in Türkiye can be found in his diaries titled 'Feldberichte' (pp. 95-104), published after his death in 1917.

Between July 14 and August 1, 1916, Boelcke visited Istanbul, Çanakkale, and Izmir. It is evident from his writings that he did not participate in any combat missions during this period. Instead, his trip was primarily for inspection, propaganda, and vacation purposes. Boelcke described his visit to Türkiye as follows (Some abbreviations have been made in the translated version):

July 14, 1916:

Traveling to Türkiye. We passed through Edirne. 

Region: Highlands, little settlement, no trees, occasional villages, but very few and small, individually placed low houses mostly thatched, mostly thatched, individually placed low houses. Parts of the region are covered with bushes. Most of the area is uncultivated, with only a few small corn fields.

Railroad: Single-track, few crossings. War makes rail traffic very difficult. Long delays at stations.

"People are poorly dressed, adorned with colorful belly bands and stunning headdresses. It's fasting time, which I believe has a significant impact on everyone. Women are also working, always wearing scarves. During our journey, we encountered a military transport vehicle. The men looked strong with tanned skin, and all their equipment seemed to be of German origin.

There was once large-scale agriculture on the shore. I saw a camel caravan grazing in a bay for the first-time and then the sea itself. There are two cannons set up against the balloons and the swimmers that shine in all colors on the shore.

St. Stefano (Yesilkoy) feels like an eastern town. I saw charming little European-style houses along the beach. It's like the Johannisthal area in Berlin. There is a radio station. Then comes Constantinople. You can't see the railroad when coming by car. The view from the car is less picturesque; old, dirt houses, but one can easily fly over them.

I was picked up at the train station by some German airmen and taken to a hotel. Later in the evening, I met with officers from the German War Ministry as well as some other gentlemen.

July 15, 1916:

We headed to the headquarters early in the day. There, I reported to Enver Pasha, who personally awarded me the War Medal. Still relatively young, Enver left a charming and energetic impression. Afterwards, accompanied by an interpreter, I visited the bazaar, a labyrinth of small streets, alleyways, and corridors selling everything imaginable. We then proceeded to Hagia Sophia, the largest mosque, and Sultanahmet, which had been converted into a barracks.

In the afternoon, we visited the 'General,' the ship where the German naval officers resided. Later in the evening, we went to Petit Champ, a garden venue where German music was played.

July 16, 1916:

In the morning, I boarded the 'General' to inspect a submarine with Lieutenant H. At noon, a Greek body passed by the hotel. The coffin lid was carried in front, exposing the body.

In the afternoon, I strolled around Galata and saw the Sultan coming out of the mosque. First, the gendarmes on horseback, followed by the bodyguards on horseback, then the aides, and finally the Sultan arriving in a carriage drawn by four horses, with the same entourage departing in reverse order.

July 17, 1916:

I was witness some flights before the afternoon. We drove through Constantinople, passing by the old Byzantine walls, ancient cemeteries, and some barracks. Then, we went through the wasteland to St. Stefano, where we visited the air station. Major S. had managed to create a fleet out of nothing, given the difficulty in obtaining supplies in the current situation. 

At noon, I was a guest of the navy aboard the 'General.' In the afternoon, accompanied by Captain D. and other gentlemen, we crossed the Bosphorus to Tarabya, where the Embassy garden beautifully housed the German cemetery of honor. Later, we visited a shoe factory in Beykoz before heading to the 'Goeben' and 'Breslau' ships. After a brief tour of both ships and dinner, I enjoyed a delightful evening concert on deck. As I departed, Captain A., the commander of the Goeben, offered me a hearty cheer.

July 18, 1916:

Today, I traveled by motorboat on the Sea of Marmara with a Turkish adjutant of S.'s. We set off for Uskudar and then crossed to the Princes' Islands, eventually arriving at Büyükada. Büyükada is akin to Berlin's Grunewald or Wannsee for the people of Constantinople—a mountainous, pine-covered island nestled in the sea, where many wealthy people had their summer residences. On Saturdays and Sundays, it's a popular destination for residents of Constantinople. We enjoyed coffee in the garden of the military mess, overlooking the sea and neighboring islands. In the evening, after visiting nearby islands (one of which houses the captured defender of Kût'ul-Amâre in a beautiful villa), we returned home.

July 19, 1916:

We set sail for Bandırma at 9:00 a.m. The Sea of Marmara was calm. Aside from a few officers, the ship was mainly populated by rural folk, including women. After spending some time in Bandırma, a town characterized by its predominantly wooden houses nestled on a mountainside with a harbor, we continued our journey by train (arranged especially for us). The trip to Lake Manyas had a somewhat gloomy atmosphere, with only a few fishing boats on the lake and numerous storks along the way. As we traveled through the Susurluk Valley, the landscape gradually transformed: more villages, well-cultivated pastures, fruit trees, and large herds of oxen and sheep came into view. Next to the railroad, there was a well-maintained road bordered by forest-like formations on the slopes. After a pleasant dinner, we slept well.

July 20, 1916:

I woke up south of Akhisar. The area is incredibly scenic, with fertile, well-cultivated land. I spotted numerous herds and camel caravans led by donkeys. The plain becomes increasingly lush as we continue our journey. Izmir is beautifully nestled on the slope of a hill.

Buddecke was at the train station with some gentlemen. I stayed at the Hotel Krämer on the seafront; from my balcony, I had a sweeping view of the entire Gulf of Smyrna. In the afternoon, after reporting to His Excellency Liman von Sanders, I visited the bazaar, which is not as large as the one in Istanbul.

July 21, 1916:

At 10 a.m., we headed to Seydiköy airport, located south of Izmir. The airmen are accommodated in a school nearby, with a division camped close to the airfield. The Turkish soldiers left a positive impression.

July 22, 1916:

In the morning, we went swimming to Karşıyaka with some men and women. Buddecke picked us up there on a yacht, and it was a wonderful trip. The view of the surrounding mountains and İzmir from the bay was stunning. 

July 23, 1916:

In the morning, we swam in Karşıyaka again and took some photos there.

July 24, 1916:

We slept in late, and in the afternoon, some gentlemen and I went on a sailing trip to the area where the planned seaplane station is located.

July 25, 1916:

In the morning, I explored the more remote areas of Izmir alone, where the scenery is much more 'oriental.' Now, I have to take the longer route to the Gallipoli) via Bandırma-Istanbul. It's disheartening to lose eight days. I could reach there in two and a half hours by plane, but Buddecke refuses to provide one. He offers a thousand reasons against it; I suspect he's following orders.

July 30, 1916:

At 10 a.m. on July 28, I embarked on a journey to the Dardanelles aboard a small gunboat. Gallipoli is a small provincial town with large barracks, some of them slightly out of the way. Some houses along the beach had been hit. By noon, we reached the town and reported to Merten Pasha. In the afternoon, I visited the airfield and took a flight over Troy-Kum Kulesi-Seddülbahir to the old British position. The flight offered stunning views, with the islands of Imbros, Bozcaada, and especially Samothrace rising beautifully from the sea. From above, British ships anchored in the Kophalo Bay of Imbros were clearly visible. Near Thalaka, a sunken Turkish cruiser and a British submarine partly remained on their sides above the waterline, while several steamers and an old French ship had run aground on the beach at Seddülbahir. The barren hilly peninsula was starkly visible. At Kilitbahir, there were large Turkish military camps.

July 31, 1916:

We traveled to Seddülbahir on a small steamer, arriving early to explore all the positions on the other side of the peninsula with a naval officer as our guide. The contrast between the Turkish and British positions was striking; the British possessed much more and better equipment. Later, I took a glance at the British landing grounds, where they had intentionally run a few steamers aground for protection. Following a quick breakfast, I flew to M. and D., and then returned to St. Stefano in the afternoon along the north coast of the Sea of Marmara.

Today marked the celebration of Ramadan Eid. Flags adorned the streets as I witnessed lively music, rhythmic drumming, bustling crowds, the sale of crescent flowers, and parades featuring flags and songs.

August 1, 1916:

After a short stop at the Ministry of War and a stroll through the bazaar, I departed from Istanbul. Enver Pasha happened to be on the same train. He instructed his adjutant to escort me to the lounge car for tea. He was quite talkative and canlı during our conversation, which was conducted mostly in German.

On August 1, Boelcke departed for Sofia aboard a Balkan train. After undertaking similar activities in this country, he returned to Berlin. His new assignment involved training German pilots and participating in active combat on the western front. Tragically, on October 28, 1916, during a dogfight in France, his plane collided with that of German pilot Erwin Böhne's, resulting in Boelcke's death at the age of 25