Dom Joly: In Japan, my monster-hunt turns into a pilgrimage

I had very mixed feelings as the Shinkansen pulled into Hiroshima station. This was a city I had always wanted to visit. My father was in the Fleet Air Arm and was flying off HMS Implacable in the Coral Sea during the Second World War. On the morning of 6 August 1945, there was a notice posted on the aircraft carrier forbidding all aircraft from flying in the Hiroshima sector until further notice. Obviously they had no idea that this was the day America dropped the first atomic bomb on that city. Young as they were, a notice like this was like a red rag to a bull.

The following day, my father flew over Hiroshima and simply could not compute what he saw. He was a modest man, but I heard him tell this story several times as a boy. So Hiroshima was always a place I longed to see and to learn more about. My father died this year, and my visit to Hiroshima was a sort of pilgrimage.

I'm actually here for my new book: I'm monster-hunting again. I read about the Hibagon, a hairy creature said to roam the hills around Hiroshima and believed by some to be a man who had been irradiated in the atomic explosion. This was too good a story to miss and also gave me the excuse I needed finally to visit Japan. Before setting off into the hills, however, I had a day to explore.

I got off the Shinkansen and pulled my suitcase along the platform towards the taxis. Birdsong was being piped through hidden speakers as though to reassure visitors that life continued here undaunted. Not that this city's visitors need any reassurance. Hiroshima is a bustling, confident sort of place and I fell in love with it immediately. At night it really comes alive, as neon of every shape and size lights up the entire city in a glow of excitement and energy.

The only visible sign of its horrific past is the Atomic Bomb Dome – a stone building built by a Czech architect in 1915. It survived the explosion although everybody inside was vaporised. Another poignant reminder are the A-bomb trees. These are trees dotted about the city that survived the blast: they are highlighted by little yellow signs attached to their hardy trunks. I rented a bicycle and rode around the place, marvelling at the infinite politeness of the Japanese bowing and smiling as I passed by. It was difficult to equate them with the country whose army fought my father with such ferocity and frequent cruelty.

To me, the dropping of the bomb is an awkward moral dilemma. Visiting Hiroshima brings home the inhumanity of the destruction reaped by the bomb that day: 80,000 people wiped out in a flash, with tens of thousands more dying from radiation-related diseases. And yet this, and the subsequent bomb on Nagasaki, brought about the Japanese surrender and possibly avoided a full-scale invasion of Japan by the allies in which hundreds of thousands would have died including, possibly, my dad.

In the museum, I gazed at the old wristwatch suspended in a glass box. The force of the blast had stopped it dead – at 8.15am, the time of the explosion on that summer morning. I wandered through the Peace Memorial Park until I came to the Peace Bell. It had a long metal battering ram suspended on a rope and you were invited to ring it. I grabbed it and struck the bell casing hard. The sound was deep and sombre and the vibrations continued to resonate in the air for a good minute as I thought of my young father, alone in his plane, gazing down on the total destruction below him.