Pyongyang is under multiple sets of United Nations sanctions over its atomic and ballistic missile programmes, and has ambitions to build a rocket capable of delivering a warhead to the US mainland – something US President Donald Trump has vowed "won't happen".
It has carried out five nuclear tests – two of them last year – and multiple missile launches, one of which saw three rockets come down in waters provocatively close to Japan last month.
Speculation that it could conduct a sixth blast in the coming days to coincide with the anniversary has reached fever pitch, with specialist US website 38North describing its Punggye-ri test site as "primed and ready" and White House officials saying military options were "already being assessed".
Trump has dispatched the aircraft carrier USS Carl Vinson and an accompanying battle group to the Korean peninsula.
"We are sending an armada. Very powerful," Trump told the Fox Business Network. "He is doing the wrong thing," he added of Kim. "He's making a big mistake."
China, the North's sole major ally, and Russia have both urged restraint, with Beijing's foreign minister Wang Yi warning Friday that "conflict could break out at any moment".
The North has reiterated its constant refrain that it is ready for "war" with the US.
Its army vowed Friday a 'merciless' response to any US provocation but diplomats in Pyongyang are more sanguine, pointing out that the North raises its rhetoric every spring, when Washington and Seoul hold annual joint exercises that it views as preparations for invasion.
None of the North's five previous nuclear tests have taken place in the month of April.
- 'Tough message' -
On past form, the parade will see Kim watch ranks of goose-stepping soldiers marching through Kim Il-Sung Square in the centre of Pyongyang, accompanied by tanks, missiles on trailers, and other materiel.
Military specialists keep a close eye on such events for clues about developments in the North's capabilities. Jeffrey Lewis, of the Middlebury Institute of International Studies said he was looking out for "the possibility of a new ICBM", adding: "There may be some surprises."
The 1950-53 Korean War ended in an armistice rather than a peace treaty and Pyongyang says that it needs nuclear weapons to defend itself against a possible US invasion.
The US cruise missile strike on Syria vindicated its stance, it said last weekend.
According to diplomats, North Korean officials have described the US president as "unpredictable" and been unnerved by his comments and actions.
Pyongyang could use the parade as a show of strength in preference to a nuclear test, analysts said.
It wanted to send "a tough message to the United States in response to the Trump administration's recent rhetoric and the military steps the United States has taken", said Evans Revere of the Brookings Institution in Washington.
Another missile launch or nuclear test "can't be ruled out", he said, but the Syria strike and Washington's implied threats "may give Pyongyang some pause".
"A parade is a highly visible but non-kinetic way of showing off capabilities," he told AFP.
The North is aiming its message at China as well as the US, analysts say.
Beijing has made clear its frustration with Pyongyang’s stubbornness but its priority remains preventing any instability on its doorstep, and it has been unnerved by the sabre-rattling.
The state-run Global Times newspaper, which sometimes reflects the thinking of China's leadership, issued an unequivocal warning to Pyongyang in an editorial this week that it "should avoid making mistakes at this time".
Pyongyang was "upset with all of its neighbours", said Bruce Bennett of the Rand Organisation and Kim needs to "demonstrate defiance".
North Korean culture is that its leaders "are supposed to reign by power", he said. "He cannot back down without looking weak and thereby facing the prospect of a coup."