Kinstone Fusion

Kinstone Fusion is the art of matching two complementary Kinstone pieces with someone else, a Mysterious Wall, or a specific marker in the overworld of The Minish Cap, resulting in a completed gold, red, blue, or green medallion with a four-leaf clover on its front. Kinstones only match with the precise complement of the other, despite the many variations and colors of kinstone pieces. Their alignment creates a form of "good luck" for Link including, but not limited to: chests containing other kinstone pieces, rupees, or inventory items, unblocked passageways, and the triggering of sidequests.

Gold Kinstone Fusions
In certain areas of the overworld, like in the Castor Wilds, in the Cloud Tops, and at the Source of the Flow, golden kinstones must be fused with specific markers such as statues or cloud forms in order to pass to the next area. The golden complements of these kinstones will always be found in the same area that requires them to be joined. Unlike the red, blue, and green kinstones which can be found anywhere, these can only be found in specific locations and can only be used where there is a specific need for them.

Mysterious Statue
The Mysterious Statues are three large statues in the Southwest corner of Castor Wilds. Link must locate three gold kinstones in the area to fuse with the three Mysterious Statues in order to proceed into the Fortress of Winds. Once each statue receives its Kinstone, its face changes to a smile and it jumps, doing progressive damage to a boulder blocking the path until the boulder is destroyed with the third and final fusing.

Each of the needed Kinstones can be found somewhere in Castor Wilds: one guarded by a Darknut in a cave to the west, a second in a cave to the north, and the third in a cave near the center.

Mysterious Clouds
The Mysterious Clouds are lumps of cloud found sporadically placed about the Cloud Tops, which respond to five different gold kinstone fusions. These five clouds, when activated by their kinstone counterparts found in the area, energize the five windmills at the center of the Cloud Tops, creating a tornado that whisks Link upward to the Palace of Winds when all five fans are whirling.

Source of the Flow
The Source of the Flow is the solid stone closed doorway located near the main waterfall in Veil Falls. It is quickly accessed by taking a route from the northeastern exit of North Hyrule Field. The entrance, however, can only be opened by one gold kinstone given to Link by Gustaf, the spirit of a former Hyrulean king, who resides in the Royal Crypt.

Mysterious Walls
Mysterious Walls are kinstone-acceptors built into the wall faces of Hyrule, commonly seen in caves that are accessed through use of the Mole Mitts. These walls, when fused with blue kinstones, will start and prolong the Goron Sidequest, and after 6 fusions with 6 different walls (along with farmer Eenie) across Hyrule, events will line up in the Goron Sidequest so that Link will have the opportunity to get another Empty Bottle, and perhaps even the Mirror Shield, due to the awakening of Biggoron over Veil Falls. Neverthelss, kinstone-fusing with these Mysterious Walls has no effect on the plot development of The Minish Cap, nor does the obtainment of the Empty Bottle or Mirror Shield that may result.

Non-Gold Kinstone Rewards
Unlike most sidequests of the series, the Kinstone Fusion quest only indirectly rewards Link. The second aspect of a successful Kinstone Fusion is to actually find the reward. After a successful match, the map screen will denote the general location and type of reward. 
 * Doors and Arrows signify newly accessible areas.
 * People signify a character having something new.
 * Scrolls signify a newly appeared treasure chest.
 * Eggs signify a newly appeared Golden Monster, such as a Golden Octorok.
 * Beanstalks signify a beanstalk which can be climbed to reach a secret area.

Trivia
The Tingle siblings keep track of successful non-gold Kinstone Fusions. After all 100 are fused, Tingle will replace the Kinstone bag with the Tingle Trophy.