In the English version, it's Sinjoh ruins. You have to have an arceus from the event and trade it over from DP.
Shinto Ruins is only obtainable if you have an Arceus.
He goes to the Shinto Ruins in Pokemon HeartGold and SoulSilver. You will see him if you do the Arceus subquest
The Sinjoh Ruins are somewhere to the north of Johto, only accessible by an Nintendo Event.
There is not a place called "Shinto Tower". There is the Sinjoh Ruins (available by event only) and various towers, however.
Arceus
First, you need an Event Arceus and you go to Shinto Ruins. Cynthia will be there as well. Then Arceus can create either Giratina, Dialga or Palkia. They will be at Level 1.
in Pokemon heartgold ruins of alph in Pokemon soulsilver ruins of alph
get an arceus and take it to ruins alph
South of Violet City.
Diagla can be found in the Shinto Ruins.
She is in the Sinjoh Ruins. This can only be accessed with bringing an event Arceus to the Ruins of Alph.
It's Rhydon.