diff --git a/lib/Bastion/Vaults/BFD.py b/lib/Bastion/Vaults/BFD.py
index 54b8609..b64c7bd 100644
--- a/lib/Bastion/Vaults/BFD.py
+++ b/lib/Bastion/Vaults/BFD.py
@@ -138,29 +138,32 @@ def push(self, asset, basis = None, **kwargs):
 		"""
 		detail  = 'F'
 		whence  = None
-		genus   = None
+		basis   = None
 		blonded = None
 		tarp    = None
 		ark     = asset.ARK
 		opts    = { }
 
-		if anchor:
+		if basis:
 			detail = 'D'
 			if isinstance(basis, BLONDE):
-				whence = basis.when.earliest
-				genus  = basis.genus
+				#-- I was given a BLONDE (a reference to a full backup)
+				anchor = basis
+				whence = anchor.when.earliest
+				genus  = anchor.genus
+				blonded = BLONDE.forDiffBackup(anchor)
+
 			if isinstance(basis, datetime.datetime):
 				whence = basis
 				genus  = "___"
-			blonded = BLONDE(asset.ARK, detail, genus)
+				blonded = BLONDE(asset.ARK, detail, genus)
 
-			tarp = "{}.tar".format(str(blonded))
 			opts['since'] = whence
 
 		else:
-			blonded = BLONDE(asset.ARK, detail, branch)
-			tarp    = "{}.tar".format(str(blonded))
+			blonded = BLONDE.forFullBackup(asset.ARK)
 
+		tarp = "{}.tar".format(str(blonded))
 
 		#-- assure that the scratch and bank paths exist.
 		(self.scratch / ark.site / ark.zone / ark.asset).mkdir(parents = True, exist_ok = True)