There are six types of jutsu: normal, special, forbidden, village, bloodline, and tier.
Normal Jutsu can be trained as long as you have the chakra, stamina, and ryo required.
Special Jutsu take three hours to train every level, in addition to chakra, stamina, and ryo costs.
Forbidden Jutsu require a scroll to train. Scrolls can be bought with ryo from other players in Trade, or from the Black Market with popularity points. You must go to the Forbidden Peak to train forbidden jutsu for the first time.
Village Jutsu can only be trained as long as you are in a certain village.
Bloodline Jutsu can only be trained with the required bloodline.
Tier Jutsu can only be trained in the correct village, and only when you have 500,000 respect points from doing diplomacy. You can then buy the required scroll from the tier shop for ryo.
Horizon is the exception to this. Instead, you need 1.5 million respect points for all of the scrolls.
Remember, you lose all your respect in a village if you leave it.