In Pokemon platinum the macanic to dig in wall at ruins?

In Pokemon Platinum, the ability to dig in walls at the ruins is unlocked by obtaining the Explorer Kit from the Celestic Town Library. Here are the steps you can follow to obtain it:

1. Head to Celestic Town and enter the library, which is located on the right side of the Pokemon Center.

2. Inside the library, talk to the librarian named Mira. She will give you a task to find the seven lithographs hidden throughout Sinnoh.

3. Collect all seven lithographs by talking to various characters and completing quests in different locations in the game.

4. Once you have collected all seven lithographs, return to Celestic Town and speak to Mira again. She will reward you with the Explorer Kit.

5. The Explorer Kit includes the ability to use the Digging Device to break down cracked walls in caves, ruins, and other locations in the game.

To use the Digging Device, simply equip it in your bag and then interact with a cracked wall. This will allow you to dig through the wall and access new areas or hidden items.