The 'Search' command in your menu is often overlooked but is incredibly important for finding hidden items and passages. Many crucial key items, such as the Sword of Erdrick and the Fairy Flute, are not found in visible chests but rather by 'Searching' specific tiles in towns or dungeons. Always try to 'Search' suspicious-looking empty spaces, corners, or even specific spots mentioned by NPCs. In towns, try searching around wells, behind buildings, or in seemingly empty rooms. In dungeons, look for discolored floor tiles or areas that seem to lead nowhere. A diligent use of 'Search' can uncover valuable treasures and progress the story.
While the original game uses the command for finding hidden relics, Dragon Quest IV evolves this mechanic by requiring players to search specific tiles to uncover secret staircases.
This emphasis on hidden floor items evolved further in Dragon Quest II, where players must search specific coordinates in the open world to uncover the five essential sigils.