*5.6. Expandability*

The components used in board games are responsible for presenting public/private information to the players. The auditory card game system proposed in this paper is a means of presenting public information to players. The previous solution was tactile presentation methods, such as adding Braille and textures to game components. The situation where the proposed method is superior to the tactile presentation method is considered to be when the components of the board game present public information to the player. The public information is presented to all players continuously, and its content changes as the game progresses. Therefore, as the game progresses, the players need to touch each and every game component to obtain public information. This behavior of the players can cause the game to lose its fun and gameplay. On the other hand, the proposed method enables the player to progress the game without touching the components of the board games. Therefore, this system can provide positive impact to a style of board game similar to that of *Uta-Karuta*, in which a small amount of public information is presented by appropriately controlling parameters, such as the placement of components and the type of sound to be presented. For example, "Concentration" [50] and "Spot it!" [51] are considered to be suitable games for auditory card game systems because they are simple games consisting of only a small amount of public information. Furthermore, the proposed method has the advantage of promoting intuitive understanding by using representational sounds. The typical cards used in the *Uta-Karuta* contain poems on themes such as love and nature. In other words, *Uta-Karuta* is not only a memorization game, but also an emotional fun game. In order to keep the original fun of the *Uta-Karuta* as much as possible, it will be important for players to be able to intuitively understand the components when they ge<sup>t</sup> information about them. Thus, games such as "Cobra Paw" [52], which is a speed game, can be considered in order to improve accessibility while maintaining the immersiveness of the game.

As described above, the auditory card game system is preferably used for presenting small amounts of public information, but it can also be used when private information is included. The solution is to wear devices such as earphones or headphones. However, a board game that includes private information requires more strategy than a game that consists only of public information. In this case, communication, such as conversations between players, is necessary, and using earphones or headphones may interfere with such communication. Therefore, it is possible to apply auditory card game systems in board games that include private information, but it may impair the enjoyment and elements of the game.

When an auditory card game system is applied to a board game with a large amount of information, the disadvantage is that it is necessary to play the sounds used in the game in order, as shown in our results, and it takes time to present all the information to the players. Although it is not impossible to apply an auditory card game system when there is a large amount of information, such as by orally explaining the movements over squares when playing a chess game without a board or pieces, it is feared that intuitiveness may be impaired.

Therefore, in order for auditory card game systems to play a role in improving accessibility while effectively guaranteeing the enjoyment of a game, we believe that games should use small amounts of public information and be played in fast-paced situations that require intuition.
