Excelsior

Heard it discussed in global chat tonight but would like to see it in black and white, i have 130 parry and 110 Bushido what issues will i have or what diminished defenses will i encounter. Also knowing that i need Bushido for special attacks with ninjitsu being a total pain in the to gain on what options do i have Also need to take into account that i use a one-handed yumi with a GoC shield.

According to OSI calculations you should have the following:
Chance of blocking with a shield: 10%
Chance of blocking with a 1-handed weapon: 34%
Chance of blocking with a 2-handed weapon: 39%

I have no idea how (if?) a shield works with a originally 2h weapon. But you can find a weak monster and just compare how often you block vs being hit. I would assume the shield would take precedence, so your chances of a successful parry are reduced - the price you pay for having an items on that were not originally designed to be used together. And ninj is pretty simple to raise if you have access to a personal trainer.
Also - not sure if having any item (relayer) in the shield slot counts as having a shield, but I would again assume it to be so. And since at 130parr/120bush you get a 5-44-49 chances I prefer not having anything in my off hand. The almost 50% chance to avoid damage is pretty good. And synergy with counterstrike bushi special (essentially an additional attackon parry) is even better.

this is an old debate. actually to tell the truth no one really knows. Colibri has mentioned before that parry/bushido conflict is a myth, but Calan (dunno) tested it and posted that there is a conflict. then again no stats or anything was posted along with it.

In My Opinion:

I have 105% reflect in Reflect Physical Damage and Trial By Fire, with insta heal. Why wouldn't i want as much damage done to me?
a bio works this way too, lots of reflect damage and healing.