The Tsi and the Yotsu

Perhaps it would be good in a few of the Sparrow apprenticed wth the Tsi.  Then they could come back to the Sparrow lands and make items for the Sparrow.  Excess items could then be traded to the Crab.  These items could be traded to the Crab.

Perhaps the Yotsu may might well want some help guarding Otosan Uchi.  Perhaps, the Sparrow clan and the Yotsu could make an agreement.  Perhaps provide station bushi at Otosan Uchi to aid them.  Perhaps training with them as well while they are there.

Perhaps also the Crane might wish to have another market for their food.  Perhaps the Sparrow could be a potential market for their products.  This might help to increase the koku in their coffers.