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Explosion site on Kuninkaansaari

The explosion on Kuninkaansaari island took place on 1.8.1906 during the Rebellion of Viapori (Sveaborg) on the southern shore of the Sand Cove (Hiekkapoukama). According to theory, it was caused by a random cannon shot by government forces at Santahamina, which hit a warehouse of 57 000 kilograms of black powder. The explosion shaped the coastline, crushed rocks, destroyed nearby buildings and killed dozens of men and caused massive forest fires.

Kuninkaansaaren ruutivaraston räjähdys

Explosion on Kuninkaansaari island

Alpo Tuurnala

The rebellion was not to begin until August 10, 1906, but the situation had changed several days earlier. Since the spring, the rebellious spirit had been grown because of poor food and treatment, salary cuts, and the death of a soldier as a victim of an officer’s brutal behavior. In Viapori, the rebellion broke out contrary to plans and too early, on July 30, 1906.


Santahamina's artillerymen started the rebellion and moved to the neighboring Kuninkaansaari Island. After this, troops in Kustaanmiekka, Vallisaari and Susisaari joined the uprising. The gunners attacked the Iso Mustasaari and tried to involve the infantry in the uprising, but they remained loyal to the government.


On 31st of July the rebels started bombing from Kuninkaansaari, and on the third day of the rebellion, August 1, the soldiers got help from the Finnish Red Guards.

In the afternoon, first of August, dozens of rebels were killed on Kuninkaansaari in a gunpowder depot explosion south of Sand Cove, which, according to the theory, was caused by a cannon shot fired by Russian government forces from Santahamina. The shot hit a warehouse containing 57,000 pounds of black powder. The blast shaped the shoreline, crushed rock, destroyed nearby buildings and killed dozens of men, as well as causing massive forest fires. The leader of the uprising, Lieutenant Yemeljanov, was also wounded. Shortly afterwards, government troops were aided by armored ships that began firing at rebel stations. The rebels had assumed they would receive aid from the ships, but this had been prepared for and the crew changed.

The explosion and bombing paralyzed the rebels' will to fight and the uprising ended the next day on 2nd of August 1906.


Sources:, Viaporin Kapina - Into Kustannus 2017, Wikipedia, Jarmo Nieminen

Cave at Kuninkaansaari Island

Cave built by the Russians near the explosion site

Maija Tuurnala 2017


Hiekkapoukama - Sand Cove

Sand Cove is located on the eastern shore of the Kuninkaansaari island. The sandy beach is the only - but not official - place for swimming on the islands. Just off the beach, there was a barracks area, a canteen and a stables built by the Russians. Now there are only stones left among the vegetation.

Sand Cove of Kuninkaansaari Island

Sand Cove of Kuninkaansaari Island

Petteri Tuurnala 2017

Largest construction projects on the island were carried out during the second half of the 19th century. The island's present appearance is a result of fortification work dating back to the 1870s. Work continued until the early 20th century. Gun battery V on the northern ridge of the island was equipped with 11-inch heavy Russian mortars, model 1877. Mortars were used during the Sveaborg Rebellion in 1906, when they were fired at Sveaborg by rebels.


Gun batteries

Näkymä merelle etelässä

At the time, Kuninkaansaari was the most powerful coastal fortress in Sveaborg. There are no actual cannons left on the island today. Old batteries can easily be found along the official route; the first coming from Vallisaari on the right side and the last at the end of the route, on the northern ridge of Kuninkaansaari.

Tykkipatteri V Kuninkaansaaren pohjoisharjanteella

Gun battery number V on the north ridge

Petteri Tuurnala 2017


Radar site

The memorial plaque of the radar "Raija" is located at Kuninkaansaari's gun battery 1. It was unveiled on 4.9.2018. The two devices purchased from Germany were given the cover name "Raija". The equipment arrived in Finland in March 1943, when Raija I was placed near Malmi Airport and Raija II on Kuninkaansaari. The device had only been introduced in Germany in November 1942 and was thus a state of the art technology.


Building a 10-tonne device took a relatively long time for the first time because there was no experience, no parts, and the German installers were not particularly qualified. Kuninkaansaari island's Raija was ready to use on May 1, 1943.


Photo: SA-kuva


The radars worked excellently and detected enemy aircrafts in time. Kuninkaansaari island's Raija II and Malmi's Raija I were used thousands of times during the three bombings.


Cooperation resulted in an exceptionally good air defense: 95% of the bombs fell outside the capital, mainly to the sea. Buildings were damaged and lives were lost, but in terms of the size of the bombings, the losses were surprisingly low. Helsinki did not become a ruin town like Dresden or Hamburg.


The radars have since been disassembled, but the location of Raija II during the war is marked with a memorial plaque.

Source: Ruotuväki-magazine, web publication 4.9.2018


Nature trail "Lyytinloikka"

Perhaps the shortest nature trail in Helsinki with a length of 70 meters, "Lyytinloikka" can be found from the corner of "The Shed" (in the yard area of the Officers' House) The trail can be used freely and there are also signs and small information boards for visitors.

Ehkä Helsingin lyhyin luontopolku, Kuninkaansaari
Ehkä Helsingin lyhyin luontopolku, Kuninkaansaari
Ehkä Helsingin lyhyin luontopolku, Kuninkaansaari

You can find the island's guide map here.

päivitetty: 8.2.2019

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