Some of the smallest children in Koriyama, a short drive from the crippled Fukushima nuclear plant, barely know what it's like to play outside - fear of radiation has kept them indoors for much of their short lives.
Though the strict safety limits for outdoor activity set after multiple meltdowns at the Fukushima Dai-ichi nuclear plant in 2011 have now been eased, parental worries and ingrained habit mean many children still stay inside.
And the impact, three years on, is now starting to show, with children experiencing falling strength, lack of coordination - some cannot even ride a bicycle - and emotional issues like shorter tempers, officials and educators say.
"There are children who are very fearful. They ask before they eat anything, 'does this have radiation in it?' and we have to tell them it's okay to eat," said Mitsuhiro Hiraguri, director of the Emporium Kindergarten in Koriyama, some 55 km (35 miles) west of the Fukushima nuclear plant.
"But some really, really want to play outside. They say they want to play in the sandbox and make mud pies. We have to tell them no, I'm sorry. Play in the sandbox inside instead."
Following the March 11, 2011, quake and tsunami, a series of explosions and meltdowns caused the world's worst nuclear accident for 25 years, spewing radiation over a swathe of Fukushima, an agricultural area long known for its rice, beef and peaches.
A 30-km radius around the plant was declared a no-go zone, forcing 160,000 people from homes where some had lived for generations. Other areas, where the radiation was not so critically high, took steps such as replacing the earth in parks and school playgrounds, decontaminating public spaces like sidewalks, and limiting children's outdoor play time.
"There are children in the disaster-stricken areas who are going to turn three tomorrow," Prime Minister Shinzo Abe said on Monday. He told a nationally televised news conference he wanted to invite as many of them as possible to the 2020 Olympics, when they will be fourth-graders, as a "symbol of reconstruction."
But this lack of outdoor play is having a detrimental affect on Koriyama's children, both physical and mentally.
"Compared to before the disaster, you can certainly see a fall in the results of physical strength and ability tests - things like grip strength, running and throwing balls," said Toshiaki Yabe, an official with the Koriyama city government.
An annual survey by the Fukushima prefecture Board of Education found that children in Fukushima weighed more than the national average in virtually every age group.
