As the consumption tax is raised to 5% to 8% from the first April, 2014, the government decided to offer ¥10,000 per child for families with young children (under some conditions) to financially support them.
Here is the link to the official announcement by the ministry of Health, Labour and Welfare.
Offial announcement by Ministry of Health, Labour and Welfare
Targets: Those who received the Child Allowance of January 2014 and whose income is below the limitation of the Child Allowance.
Target Children: Basically the target children of the Child Allowance of January 2014, except the recipient of the temporary welfare allowance or the welfare benefit.
Amount: 10,000 yen per child
Procesure (Application): Go to the counter of your local ward/city office where you belonged on 1st January 2014*. Then the local government will judge if the person in question has right to receive the allowance.
*Even if you live in Yokoahama now (in April 2014 for instance), if you lived in some other city on 1st January 2014 and registered as the citizen there at that time, you must apply to the city, not Yokohama.
Here is the link to the webpage of the city of Yokohama, but no detail is updated at the moment (26th March 2014) and is written "We will update the detail as soon as it is decided". So we have nothing to do right now.