How Can I insert date wrriten in Japanese to the ES?

Hello.
I'd like to insert date written in Japanese.

I tried to insert date by following command.

curl -XPUT 'http://localhost:9200/posts/post/5’ -d {"contents":"日本語のテストです。","id":"5","name":"斉藤はじめ","userId":"5"}

but It occurred the following error.

{"error":"MppaerParsingExceptuon[failed to parse [contents]]; nested: JsonParseException[Invalid UTF-8 start byte 0x93\n at [Source: [B@61fd643e; line: 1, column: 15]]; "," status":400}

How Can I insert date wrriten in Japanese to the ES?
Could you please help me.

Which OS do you use?

If JSON is enclosed by single quotes, how about?

Thanks for your comments.
I used the _bulk API, so I could insert the date written in Japanese.
I guess that this problem attributed to the Encode of the date.

When I created the date,We saved the data in Shift-JIS format.
this is the problem, maybe.

I created the date in UTF-8 format and using _bulk API.
I inserted the date correctly.

thanks for your helping!!

sincerely.