**1. Introduction**

Games as a means for social interaction and enjoyment were not initially included in digital technology. Multiple players had to exist in the same physical environment, and played game by manipulating tangible components made of wood or stone [1]. However, the development of digital technology has led to digital games, making it possible to play games without being in the same physical environment [1]. In spite of the shift from board games (which we define as all non-digital games) to digital games, board games have continued to be popular.

Playing board games is important for promoting interactive socialization of participants and improving problem-solving and communication skills [2]. Moreover, sharing a physical environment and game components facilitates concentration and verbal communication, which can help enhance relationships [3,4].

However, most board games are difficult to play with people with visual impairments because they are designed on the assumption that visual contact can be seen [5,6]. Further, board games can cause more difficulty due the need for interaction and special manipulation with the game components.

Although board games have these accessibility issues, the positive impact of board games on players is considered to be particularly significant for people with visual im-

**Citation:** Miyakawa, H.; Kuratomo, N.; Salih, H.E.B.; Zempo, K. Auditory *Uta-Karuta*: Development and Evaluation of an Accessible Card Game System Using Audible Cards for the Visually Impaired. *Electronics* **2021**, *10*, 750. https://doi.org/ 10.3390/electronics10060750

Academic Editors: Jun Dong Cho and Juan M. Corchado

Received: 26 January 2021 Accepted: 15 March 2021 Published: 22 March 2021

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

pairments. Most people with visual impairments experience more social isolation and difficulties in interpersonal relationships due to their disability [7]. The positive effects of board games, such as improving problem-solving and communication skills, can solve these problems. In addition, to manipulate game components one's own self and participate in the game without the help of anyone, it could be able to contribute to further strengthening autonomy and increasing satisfaction of people with visual impairments. These contributions will able to promote the ability to live powerfully with disabilities: resilience [8,9]. Thus, it is important to give people with visual impairments the chance to have access to games for effective inclusion and participation in society. The efforts to improve board game accessibility have been made by devising rules or structures for the cards/pieces used in board game. "The Arabian Pots" [10] and "Nyctophobia" [11], which are typical examples of board games whose rules are designed for people with visual impairments, require only the ability to distinguish sounds. On the other hand, the newer versions of "Uno" [12] and "Hanabi" [13] are games that ensure accessibility by devising structures for the cards/pieces that they use. They use Braille or larger-than-usual cards to represent different colors and numbers for people with visual impairments. The solutions to making the cards/pieces used during board games accessible for people with visual impairments are mainly limited to enlarging the cards/pieces themselves or using tactile presentation. The former is the simplest solution, but it has the disadvantage of not allowing inclusion for completely blind players. The latter has the advantage of the inclusion of all visually impaired people in existing board games, but this solution alone is not enough to apply to all board games. It is necessary to memorize Braille script, as well as textures and their corresponding information, in advance, which is not intuitive. In other words, a solution that only presents tactile sensations has a risk of diminishing the enjoyment of the board game when integrated into existing games.

In this paper, we propose an auditory card game system that presents the card's contents by sound [14], with the aim to develop a board game that can be played in the same way by all players, regardless of whether they have a visual impairment or not. This is one of the solutions for making cards/pieces used during board games accessible for people with visual impairments. The purpose of this paper is to determine whether the game allows for fair competition for people with visual impairments and to clarify the effects of the valuable parameters of the system on the players. The remainder of this paper is organized as follows: in Section 2, we describe existing research and products from the community on games that are accessible to people with visual impairments. In Section 3, we introduce the configuration of the proposed game system. In Section 4, we describe the overview and results of a subject experiment on a new game that applies the proposed system to an existing card game. In Section 5, we investigate each valuable parameter of the system and explain the appropriate game design based on the results of various existing studies. Finally, the limitations of this study are described, followed by the conclusion.

### **2. Related Works**

To solve accessibility issues for people with visual impairments in digital/non-digital games, various efforts have been deployed. In this section, we first describe the efforts by researchers and the community on the accessibility of digital games for the visually impaired. Next, we describe these efforts with respect to a non-digital game, breaking it down by the role of the components used in the game. Finally, we explain where our proposed system stands and contribution in relation to previous works.

In the digital game domain, audiogames that can be played with audio only are mainstream. Although audiogames is very small market compared to that of computer games, a lot of people with visually impaired enjoy audiogames, and the players and developers community is enhanced on internet site by introducing new audiogames and sharing player reviews [15]. However, audiogames do not appeal as much to sighted people because they don't have visual information. In fact, most audiogames are not interesting for most people, and the majority of players are people with visual impairments.

To create accessible games that can interest both camps, researchers have been contributing to the development of games that are not only audio but also visual and/or tactile. For example, "Terraformers" [16] uses sound propagation to convey the proximity of obstacles. "Terraformers" [16] and "AudioBattleship" [17] give feedback for every action using a voice over. "Sonic-Badminton" [18] enables play regardless of visual impairment by presenting the position of the wings of the badminton with stereophonic sound. Examples of the use of tactile sensation include "TiM games" [19] and "Digital Clock Carpet" [20] which can navigate in 2D environments by presenting different tactile stimulation with various materials. Further, "Kinaptic" [21] has enabled people with visual impairments to play a chasing game in a virtual environment by using sound and tactile feedback. These games aim to have same level of win rates between people with visual impairments and sighted people.

On the other hand, board games are far behind digital games when it comes to accessibility. In addition, most board game accessibility efforts have come from the community such as "Board Game Geek" [22] and "Meeple Like us" [23]. These efforts have been established by devising the rule or structure of the cards/pieces used in the board game. "The Arabian Pots" [10], which is a typical example of a board game, whose rules are designed for people with visual impairments, requires only the ability to distinguish sounds. It was designed after repeated tests so that only blind people can actually play. "Nyctophobia" [11] is a tactile maze game that does not assume the use of visual information. Players cannot see the board and have to rely on touch to play the game. On the other hand, "Splendor" [24] is a typical example of a game that ensures accessibility by devising the structure of the cards/pieces used in the board game. The first version of "Splendor" [24] used color as the only factor required to acquire a card, so players who could not distinguish between colors could not play the game, but the addition of iconography to the newer version makes this the game accessible to this audience. Similarly, the newer version of "Uno" [12] uses Braille to represent different colors and number. "Hanabi" [13] designed for people with visual impairments, has been modified to use larger-than-usual cards and card holders, but cannot be played by blind people because they still do not use non-visual modalities.

These board game's pieces and cards are generally called components, and they play the role of input/output interfaces between the game world and the players. The functions and entertaining properties of the components are realized because the components are real objects. The functions of components can be broadly classified into the presentation of information to all players and the presentation of information to specific players. In this paper, we define "public information" as the information presented to all players. They corresponds to the function of pieces used in Othello, Chess and Shogi. In contrast, we define "personal information" as the information presented to specific players. They corresponds to the function of deal cards used in Uno and Poker. Although players progress through the board games by manipulating the components, the physical constraints of the components may cause accessibility problems.

Table 1 shows a comparison of the aforementioned accessible board games classified according to the function of the components and the input/output between the players and the interfaces.

In order for people with visual impairments to correctly recognize the components of board games, it is necessary to use hearing and tactile sensation instead of sight. The work of making components accessible can also make existing board games accessible, which can also be an opportunity for people with visual impairments to enter the board game community of the sighted. As shown in Table 1, tactile presentation has been the main solution when components present public information in previous studies. The only solution that uses auditory stimuli is online competition, which does not guarantee face-toface communication. Similarly, when the component presents private information, tactile presentation is the main solution. However, unlike public information, private information cannot be presented to other players, so it is not appropriate to use auditory stimuli that

can be transmitted to an indefinite number of players. Even if a headphone/earphone is used, it may interfere with face-to-face communication.



In this study, we proposed an auditory card game system that presents a card's contents with auditory stimuli to all players, towards playing equally with others, regardless of whether they have a visual impairment or not. This is one of the solutions that presents public information of board games. Making board games components accessible will make it easier for visually impaired people to play existing board games with sighted people. Tactile presentation is the mainstream method for people with visual impairments to access board game components on their own, but it has the disadvantage that it requires touching every time the information is needed. This disadvantage cannot be applied when the game situation can change by touching board game components or when the game situation changes quickly. Furthermore, it is necessary to memorize Braille and textures and their corresponding information in advance, which is not intuitive. On the other hand, by presenting components with sound, players can obtain information about a component's contents and locations without touching them. Filho et al. [1] developed a game with textured card content to ensure accessibility for the visually impaired and designed guidelines, but some of their experimental participants requested audio feedback from the components. In addition to expanding the range of accessible board games, the use of auditory stimuli has the potential to increase immersion and make the game more intuitive and enjoyable. Furthermore, by digitizing the components of a board game, some of the physical constraints of the components can be lifted. This allows us to assign multiple components to a single device, or to increase the range of strategies by intentionally rewriting the information of the components. The final game design policy is to make the game fun for everyone, regardless of the degree of visual impairment.

### **3. Auditory Card Game System**
