Ice break has been attracting attention as a tool for enhancing communications during the first encounter. Previous research showed that collaborative tabletop games are effective for ice break. However, few research discuss the factors of these games that influence this enhancement. In this research, we developed a tabletop game where a piece on a board is manipulated by inclining the board with four levers to navigate the piece to follow the predefined path. Our hypothesis is that communication may be enhanced by counter-intuitive behavior of the piece, such as climbing up the slope that is against the laws of physics on the earth. Though what the players manipulate is the real levers, what they see is virtual board and piece rendered through MR device (HoloLens2). In this research we have implemented two behaviors of the piece, one is normal gravity behavior where the peace goes down the slope while the other is anti-gravity behavior where the peace climbs up the slope. To evaluate the effect of the counter-intuitive behavior on the enhancement of the communication, we have conducted experiment where the pair of players played the game under two different conditions. The results of the five-point Likert scale questionnaire demonstrated that the counter-intuitive behavior had positive effect on the freshness and interestingness of the game while it had no effect on the difficulty of the cooperation. However, it was confirmed that the verbal communication between the players increased 6.7% in average which partially support our hypothesis.