Shodai-Sama is leader from SENJU Clan and then again he is the only one (as far as we know) who can tame the bijuu using his chakra..Since Tsunade is grandaughter of Shodai-Hokage, is that mean that Tsunade is a part of SENJU Clan??..I just think the POSSIBILITY that Tsunade will develope a JUTSU to controlled BIJUU like Hokage Shiki Jijun Jutsu,maybe more like her own version and teach it to SAKURA..