When North Korea first hinted it had a hydrogen bomb, it was dismissed rather hastily and was not considered an actual threat. Even now, after being told that the isolated country has successfully tested a miniaturised hydrogen nuclear device, there is still scepticism among experts and officials. These sources doubt Pyongyang has actually managed to achieve such a major advance in its strike capability, yet the North Korean establishment is probably the most proficient in the world in terms of calculating the benefits and risks of ratcheting up tensions and alienating even its closest allies to get what it wants.

The nuclear test comes just a few months ahead of what is scheduled to be the seventh congress of the country's ruling party, which was founded 70 years ago, and two days before what is believed to be Kim Jong-un's birthday; he is understood to be in his early 30s.

Kim Jong-un has gone to great lengths to conceal his true intentions – just as he strives to seem powerful and important in the photos released by the North Korean Central News Agency (KCNA) where he is constantly surrounded by employees who are either rapidly taking notes, laughing (for a reason that is usually unknown) or watching his every move.

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North Korean leader Kim Jong Un visits the Kumsusan Palace of the Sun to mark the 21st anniversary of the death of founder Kim Il SungReuters
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North Korean leader Kim Jong Un greets North Korea's female soccer team as they arrive at Pyongyang International Airport on Monday after winning the 2015 EAFF East Asian Cup in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong-Un giving the final order for the launch of the Unha-3 rocket, carrying the satellite Kwangmyongsong-3, at the general satellite control and command center in Pyongyang, North KoreaGetty Images
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North Korean leader Kim Jong Un visits the Samchon Catfish Farm in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un issues instructions while visiting the construction site of the Mirae Scientists Street in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un gives field guidance at the construction site of the Fishery Station in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un visits Pyongyang Biological Technology Research Institute under KPA Unit 810 in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un visits Farm No. 1116, under KPA (Korean People's Army) Unit 810 in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un watches a performance, "Song of Youth Following the Sun", given by the Art Squad of the Central Committee of the Kim Il Sung Socialist Youth League in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un examines boots made at the Wonsan Shoes Factory in Pyongyang, North KoreaReuters

While North Korea uses its nuclear tests to project power abroad, they are also a domestic propaganda tool for its third-generation dictatorship.
The years since Kim Jong-un took power following his father Kim Jong Il's death in 2011 have been turbulent, marked by high-level purges and irrational executions.

Speaking about the nuclear test, which was conducted at 10am local time (01:30 GMT), according to North Korea's official KCNA news agency, Kim wrote, in what North Korean state TV displayed as a handwritten note, the words: "Let the world look up to the strong, self-reliant nuclear-armed state."

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North Korean leader Kim Jong Un (front) visits the Kumsusan Palace on the Day of the Shining Star in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un visits the May 9 Catfish Farm in this undated photo released by North Korea's Korean Central News Agency (KCNA) in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un (C) and senior Chinese Communist Party official Liu Yunshan (L) react during celebration of the founding of the ruling Workers' Party in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un tours the Sci-Tech Complex in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong-Un watches a firing contest of the KPA artillery units in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un visits the Pyongyang Taegyong Laver Processing Factory in Pyongyang, North KoreaReuters
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North Korean leader Kim Jong Un smiles as he attends a flight training session by female fighter pilots Jo Kum Hyang and Rim SolReuters
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North Korean leader Kim Jong Un visits the Wonsan Baby Home and Orphanage, North KoreaReuters