law4all

this will show how labor contract will be established.

A labor contract shall be established by agreement between a worker and an employer on the basis that the worker shall work by being employed by the employer and the employer shall pay
wages for such work.

In cases where a worker and an employer conclude a labor contract, if the employer had informed the worker of the rules of employment that provide for reasonable working conditions, the contents of the labor contract shall be based on the working conditions provided by such rules of employment; provided, however, that this shall not apply to any portion of the labor contract in which the worker and the employer had agreed on working conditions that are different from the contents of the rules of employment.

A worker and an employer may, by agreement, change any working conditions that constitute the contents of a labor contract.
Change to the Contents of a Labor Contract Based on Rules of Employment
An employer may not, unless agreement has been reached with a worker,
change any of the working conditions that constitute the contents of a labor contract in a manner
disadvantageous to the worker by changing the rules of employment; provided, however,
that this shall not apply to the cases set forth in the following

In cases where an employer changes the working conditions by changing the rules of employment, if the employer informs the worker of the changed rules of employment,

and if the change to the rules of employment is reasonable in light of the extent of the disadvantage to be incurred by the worker,
the need for changing the working conditions,
the appropriateness of the contents of the changed rules of employment,
the status of negotiations with a labor union or the like,
or any other circumstances pertaining to the change to the rules of employment,
the working conditions that constitute the contents of a labor contract shall be in accordance with such changed rules of employment; provided, however,

that this shall not apply to any portion of the labor contract which the worker and the employer
had agreed on as being the working conditions that are not to be changed by any change to the rules of employment,