Japanese Naval Ensign – Kyokujitsu-ki (Size 4)

Full view of the flag. Standard 16-ray Kyokujitsu-ki design on wool bunting.

🇯🇵 Japanese Naval Ensign – Kyokujitsu-ki (Size 4)

Material: Wool
Construction: Hand-sewn panel construction with rope hoist and reinforced edges
Markings: Printed in Japanese “海軍 四” ("Navy – No. 4")
Approx. size: 170 × 225 cm (2:3)

🧵 Description

This is an original Kyokujitsu-ki (“Rising Sun Flag”) of the Imperial Japanese Navy, issued in Size 4 and made of coarse wool bunting. The flag is entirely hand-sewn, featuring 16 sun rays radiating from a red central sun, constructed from individual panels. The corners are reinforced with additional stitching, and both ends of the hoist are equipped with braided rope loops sewn directly into the hem.

The cloth is stamped on the hoist with the characters 海軍 四 ("Kaigun – 4"), identifying it as a naval flag of the Imperial Japanese Navy, Size No. 4. It shows typical period wear, including some moth damage and age staining, but remains in excellent structural condition.

🏯 Historical Context – Glen Line Building, Shanghai 1945

According to provenance, this flag was captured by a U.S. Marine in 1945 from the Glen Line Building, located at No. 28 Beijing Road on The Bund, Shanghai.

• Originally serving as the U.S. Consulate, the building was sold to Japanese authorities shortly before the occupation of Northern China.
• During World War II, it reportedly housed the German Embassy on upper floors and the Yokohama Specie Bank on the lower levels.
• From 1937 until Japan’s capitulation in 1945, it served as a Japanese naval administration site, with the Rising Sun flag raised daily.

🏗️ Size Suitability – Architectural Analysis

The Glen Line Building is a 7-storey structure built in 1922, measuring approximately 27 meters in height. The flag measures 170 × 225 cm, or about 6% of the building’s vertical height.

This is consistent with Imperial Japanese Navy standards:

• Size 4 flags were used for land-based installations, offices, and shore commands.
• From a street-level perspective, such a flag would have been clearly visible when flown from the roof or upper levels, without overwhelming the structure.

The proportions between flag and building height confirm the flag’s functional plausibility as a ceremonial or administrative ensign during the Japanese occupation of Shanghai.

🈸 Markings and Interpretation

Stamped on the hoist in black ink are the following kanji:

海軍 四
Kaigun – 4

Where:

• 海軍 (Kaigun) = Navy
• 四 (Yon / 4) = Standard flag size

This combination was part of a standardized Japanese naval marking system used from the early 20th century up to 1945.

📷 Image Gallery

Hoist area with Japanese naval stamp “海軍 四” – “Kaigun – 4” (Navy – Size 4).

Upper corner detail showing moth damage and age wear typical of original WWII-era wool flags.

Braided rope hoist stitched into reinforced corner with thick triangular seam panels.

Opposite end of hoist with same rope construction and hand-stitched seams.

Close-up of rope loop showing original period construction without modern replacements.

💰 Rarity and Value

Original WWII-era naval Rising Sun flags are increasingly rare on the collectors’ market. This example, marked with “Kaigun – 4” and linked to a known capture site, represents a high-value artifact of Japanese naval history. Similar flags in comparable condition and size often command premium prices due to their wartime provenance, construction quality, and iconic status.

📚 Sources and References

• First-hand provenance (U.S. Marine estate, 1945)
• “The Glen Line Building” – Shanghai Architectural Heritage Archives
• Yokohama Specie Bank occupation records, 1937–1945
• Comparative Imperial Japanese Navy flag markings and hoist construction
• Naval flag size charts and Japanese military textile typologies (1920s–1940s)