The rogue state is said to be finalising plans to launch four Hwasong-12 rockets towards the Pacific island territory, which is home to some 163,000 people.
It will take roughly 14 minutes for the missiles to reach their intended target more than 2,000 miles away, and the local government in Guam has issued guidance to residents on how best to protect themselves from a nuclear attack.
But in Hiroshima, which in 1945 became the first city in history to be hit by a nuclear weapon, the situation has brought back horrific memories and stoked fresh fears of a repeat attack.
North Korea regularly promises to reduce Japan to “debris” in state-sponsored news broadcasts but these sabre-rattling claims have escalated wildly in recent days.
In a statement last week, Pyongyang named Hiroshima as one of three Japanese prefectures its missiles could fly over on their way to Guam, along with Shimane and Kochi.
Yesterday Japan’s defense ministry deployed the Patriot Advanced Capability-3 (PAC-3) missile defence system to Self Defence Forces (SDF) bases in all three cities as a precaution.
An SDF spokesman told CNN there was no plans to shoot the North Korean missiles down as they passed overhead but had rather been deployed “just in case”.
Another senior analyst said the only scenario in which Japan would intercet would be if one of the Hwasong rockets fell short.
However the escalation of tensions between the US and North Korea in recent weeks has made the prospect of nuclear war terrifyingly plausible.
For most people on earth the reality of that situation is unimaginable – but for the people of Hiroshma, it is a part of their grim recent history.
On August 6, 1945, pilot Paul Tibbets flew the US B29 bomber Enola Gay – named after his mother – over Hiroshima and dropped the atomic bomb code-named “Little Boy”.
As a direct result of the 20 kiloton blast, 66,000 people died and a further 69,000 were injured.
Tamio Ishida, 59, whose father was a survivor, told the Washington Post: “Tensions have risen and many people in Hiroshima share a sense of urgency.
“What if that young leader [Kim Jong-un] pushes a nuclear weapons launch button? I think that neighbouring Japan has a risk of being hit.”
The threat of war has cast a long shadow over this month’s 72nd anniversary commemorations of the 1945 bombing.
Nuclear policy expert Jeffrey Lewis, from the Middlebury Institute, said it had ben a “depressing year”.
“This is a year where we spend a lot of time talking about, how instead of proposing things to make the world a little bit better, we would propose things to stop the world from getting worse,” he told CBC.
Concerns were raised earlier this week whether Japan’s defence system was strong enough to intercept missiles fired in East Asia.
North Korea observer 38 North said Japan’s likelihood of taking down a missile is “limited if not improbably”.
The Washington-based group warned: “In fact, the probability that the North Korean ICBM test will fail on its own is significantly higher than the probability of success.
“SM-3 interceptors have never been tested against an ICBM, nor have they been tested against any missile in the boost or ascent phase of flight.”