"Ooban" is very Rare size of the stone, HUGE stone
This Size is super Rare for Jnats thats why the high price !
This one is Just perfect rectangular amazingly clean, first time i see so clean stone that is so big
Very nice stone for beginners in Japanese Natural stones.
Super easy to use on tools and knives ! 
Produce mud quickly without using Nagura and quite fast stone too ! 
Makes very nice hazy kasumi finish, and very nice stone for Honyakis or laminated blades.
Beautiful even green colors. Very smooth feeling while sharpening ! 
No lines or inclusions at all !
Colector Grade ! 
 
Size: 230mm 107mm 33mm
 
             
                                                 
                                                 
                                                 
                                                 
                                                 
                                                 
                                                 
                                             
                                             
                                             
                                             
                                             
                                            