On the basis of ohmic and neutral beam heating experiments in JT-60U, the discharge regions in tokamaks are characterized in terms of the internal inductance li and the effective safety factor at the edge, qeff, in the low beta region. Stable discharges have medium li values, and disruptive discharges occur both in higher and lower li regions for a given qeff. There is also a boundary of li below which sawtooth free discharges occur. Another boundary of li corresponds to the quasi-stationary current distribution profiles, along which the maximum value of rinv/a (sawtooth inversion radius/minor radius) is almost proportional to 1/qeff. At a given qeff value, rinv/a increases with increasing li. Concerning L-mode confinement, the H-factor (H = τE/τEITER89P) is almost proportional to li0.8 over a wide range of qeff (qeff = 2-14). The degradation of confinement in the low q region (qeff < 4-5) in the L-mode is caused by the effects of li and sawtooth activity. In the low q region, H/li0.8 decreases with decreasing sawtooth period τSW and with increasing rinv/a. The degradation due to sawteeth is stronger at lower qeff. A new confinement scaling law for the H-factor (Hsc) in the L-mode is obtained by including the effects of li and sawteeth: Hsc = (Y+fτsw)li0.8 where τsw < (c-Y)/f, and Hsc = cli0.8 when τsw > (c-Y)/f, where f = 10.0/qeff2, Y = c-0.96(rinv/a) and c = 0.92