The Blue Card (ブルーカード Burū Kādo?) contains an algorithm that was created by Shibumi. It exists to create digital connections and does so in any way possible, much like the Digi-Gnomes. The Blue Cards use emotions and faith to make ideas real, and as a result, any card can be transformed into a Blue Card once you understand how they work. Also, due to this nature, it can be used in many different ways.
The swipe of a Blue Card into a card scanner D-Power, linking a human together with a Digimon as partner and Tamer. When this happened, a Digimon in the Digital World would be brought across the dimensions and bio-emerge the Real World.or a similar card reading device can transform the device into a
Kazu created a facsimile of the Blue Card, which Takato later used to help Growlmon digivolve to WarGrowlmon.
Similarly, the Blue Card algorithm was used to summon Grani into the Real World.
The Blue Card algorithm was also used to bring Digimon across dimensions into from the Digital World into the Real World.
Digimon World 3
The Blue Card is used to go between the east and south sectors. When Junior talks to the tricky Guilmon, he gives him a false Blue Card called a 8lue Card. When Junior talks to him again in the basement of the Forest Inn, he gives him a real Blue Card.