TABLE 1.

Demographic characteristics (N = 335).

Variable	Category	n (%)
Time spent on online gaming (per weekday)	less than 1 h	92 (27.5%)
	1 to less than 2 h	124 (37.0%)
	2 to less than 3 h	66 (19.7%)
	3 to less than 4 h	22 (6.6%)
	4 to less than 5 h	10 (3.0%)
	5 to less than 6 h	5 (1.5%)
	6 h or more	10 (3.0%)
Time spent on online gaming (per weekend)	less than 1 h	47 (14.0%)
	1 to less than 2 h	42 (12.5%)
	2 to less than 3 h	75 (22.4%)
	3 to less than 4 h	60 (17.9%)
	4 to less than 5 h	35 (10.4%)
	5 to less than 6 h	24 (7.2%)
	6 h or more	45 (13.4%)
Time zone on online gaming (per weekday)	4:00–8:00	8 (2.3%)
	8:00–12:00	6 (1.7%)
	12:00–16:00	1 (0.3%)
	16:00–20:00	59 (17.2%)
	20:00–0:00	121 (53.1%)
	0:00–4:00	13 (3.8%)
Time zone on online gaming (per weekend)	4:00–8:00	11 (3.3%)
	8:00–12:00	38 (11.3%)
	12:00–16:00	79 (23.4%)
	16:00–20:00	53 (15.8%)
	20:00–0:00	54 (16.1%)
	0:00–4:00	9 (2.7%)
The style of in-game purchases	Non-purchase users	232 (69.3%)
	Planned purchase users	56 (16.7%)
	Unplanned purchase users	47 (14.0%)
Monthly allowance	Less than 1,000 JPY	15 (4.5%)
	1,000–1,999 JPY	84 (25.1%)
	2,000–2,999 JPY	66 (19.7%)
	3,000–3,999 JPY	109 (32.5%)
	4,000 JPY or more	34 (10.1%)

JPY = Japanese Yen (1,000 JPY = 9.12 USD).