Alright now we know these two clans have been basically at war with one another since their ancestors. But here is my new theory on why the Uchiha's had such a hard time with the Senju clan.
The Senju's techniques were highly unpredictable.
Hashirama Senju the ONLY Senju that we know of that possessed the Kekkei Genkai of Mokuton (Wood Release) thus being unpredictable of where it would appear. Reason so many have been able to counter Tenzou's (Yamato's) is because his is as he even puts it pale in comparison of Hashirama's version of it.
Tobirama Senju could use ANY Water technique he desired without there needing to be a water source available to him thus making his attacks highly unpredictable for the Uchiha's then you have to take into account that he knew Impure World Resurrection well actually he created it. Also he was highly skilled in Space-Time techniques......to what degree and what techniques we still don't know.
Who knows what the other original Senju Clan members could do in their time. Whatever it was was enough to fight off 2 Mangekyou Sharingan users AND then Madara with his Eternal Mangekyou Sharingan
The Senju's techniques were highly unpredictable.
Hashirama Senju the ONLY Senju that we know of that possessed the Kekkei Genkai of Mokuton (Wood Release) thus being unpredictable of where it would appear. Reason so many have been able to counter Tenzou's (Yamato's) is because his is as he even puts it pale in comparison of Hashirama's version of it.
Tobirama Senju could use ANY Water technique he desired without there needing to be a water source available to him thus making his attacks highly unpredictable for the Uchiha's then you have to take into account that he knew Impure World Resurrection well actually he created it. Also he was highly skilled in Space-Time techniques......to what degree and what techniques we still don't know.
Who knows what the other original Senju Clan members could do in their time. Whatever it was was enough to fight off 2 Mangekyou Sharingan users AND then Madara with his Eternal Mangekyou Sharingan