In honor of My Nintendo and Miitomo releasing in North America and Europe, Nintendo is sending promotional e-mails to get the word out. At first the e-mail looks like your standard marketing e-mail, but if you scroll down, those who had a Club Nintendo account prior to it ending should receive a code in that e-mail for 200 free platinum coins. While this amount isn’t much, it is enough to get Picross: The Legend of Zelda: Twilight Princess today.
To redeem the code, simply go to My Nintendo, look for the menu option to the top left and then select redeem code. There you can enter the code, though you’ll have to remove the hyphens to enter the full code. After that you should receive 200 coins and be well on your way to getting Picross or another reward.
For those wondering about Picross: The Legend of Zelda: Twilight Princess, it’s a mere 501 blocks and does not give gold coins.