diff --git a/core/contracts.go b/core/contracts.go
new file mode 100644
index 0000000000..cc07ae7e01
--- /dev/null
+++ b/core/contracts.go
@@ -0,0 +1,49 @@
+package core
+
+const ( // built-in contracts address and code
+	ContractAddrURLhint = "0000000000000000000000000000000000000008"
+	//ContractCodeURLhint = "0x60b180600c6000396000f30060003560e060020a90048063d66d6c1014601557005b60216004356024356027565b60006000f35b6000600083815260200190815260200160002054600160a060020a0316600014806075575033600160a060020a03166000600084815260200190815260200160002054600160a060020a0316145b607c5760ad565b3360006000848152602001908152602001600020819055508060016000848152602001908152602001600020819055505b505056"
+	ContractCodeURLhint = "0x60003560e060020a90048063d66d6c1014601557005b60216004356024356027565b60006000f35b6000600083815260200190815260200160002054600160a060020a0316600014806075575033600160a060020a03166000600084815260200190815260200160002054600160a060020a0316145b607c5760ad565b3360006000848152602001908152602001600020819055508060016000848152602001908152602001600020819055505b505056"
+	/*
+		contract URLhint {
+			function register(uint256 _hash, uint256 _url) {
+				if (owner[_hash] == 0 || owner[_hash] == msg.sender) {
+					owner[_hash] = msg.sender;
+					url[_hash] = _url;
+				}
+			}
+			mapping (uint256 => address) owner;
+			mapping (uint256 => uint256) url;
+		}
+	*/
+
+	ContractAddrHashReg = "0000000000000000000000000000000000000009"
+	ContractCodeHashReg = "0x60003560e060020a9004806331e12c2014601f578063d66d6c1014602b57005b6025603d565b60006000f35b6037600435602435605d565b60006000f35b600054600160a060020a0316600014605357605b565b336000819055505b565b600054600160a060020a031633600160a060020a031614607b576094565b8060016000848152602001908152602001600020819055505b505056"
+	//ContractCodeHashReg = "0x609880600c6000396000f30060003560e060020a9004806331e12c2014601f578063d66d6c1014602b57005b6025603d565b60006000f35b6037600435602435605d565b60006000f35b600054600160a060020a0316600014605357605b565b336000819055505b565b600054600160a060020a031633600160a060020a031614607b576094565b8060016000848152602001908152602001600020819055505b505056"
+	/*
+		   contract HashReg {
+			function setowner() {
+				if (owner == 0) {
+					owner = msg.sender;
+				}
+			}
+		   	function register(uint256 _key, uint256 _content) {
+				if (msg.sender == owner) {
+		   			content[_key] = _content;
+				}
+		   	}
+			address owner;
+		   	mapping (uint256 => uint256) content;
+		   }
+	*/
+
+	ContractAddrSwarm = "000000000000000000000000000000000000000a"
+	ContractCodeSwarm = "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"
+	// see bzz/bzzcontract/swarm.sol
+
+	BuiltInContracts = `
+	"` + ContractAddrURLhint + `": {"balance": "0", "code": "` + ContractCodeURLhint + `"	},
+	"` + ContractAddrHashReg + `": {"balance": "0", "code": "` + ContractCodeHashReg + `"	},
+	"` + ContractAddrSwarm + `": {"balance": "0", "code": "` + ContractCodeSwarm + `"	},
+	`
+)
diff --git a/core/genesis.go b/core/genesis.go
index 8ef1e140fe..f44f0229f1 100644
--- a/core/genesis.go
+++ b/core/genesis.go
@@ -3,12 +3,12 @@ package core
 import (
 	"encoding/json"
 	"fmt"
+	"math/big"
 	"os"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/params"
 )
 
 /*
@@ -18,11 +18,13 @@ import (
 var ZeroHash256 = make([]byte, 32)
 var ZeroHash160 = make([]byte, 20)
 var ZeroHash512 = make([]byte, 64)
+var GenesisDiff = big.NewInt(131072)
+var GenesisGasLimit = big.NewInt(3141592)
 
 func GenesisBlock(db common.Database) *types.Block {
-	genesis := types.NewBlock(common.Hash{}, common.Address{}, common.Hash{}, params.GenesisDifficulty, 42, nil)
+	genesis := types.NewBlock(common.Hash{}, common.Address{}, common.Hash{}, GenesisDiff, 42, "")
 	genesis.Header().Number = common.Big0
-	genesis.Header().GasLimit = params.GenesisGasLimit
+	genesis.Header().GasLimit = GenesisGasLimit
 	genesis.Header().GasUsed = common.Big0
 	genesis.Header().Time = 0
 
@@ -56,7 +58,14 @@ func GenesisBlock(db common.Database) *types.Block {
 	return genesis
 }
 
+const (
+	TestAccount = "e273f01c99144c438695e10f24926dc1f9fbf62d"
+	TestBalance = "1000000000000"
+)
+
 var genesisData = []byte(`{
+	"` + TestAccount + `": {"balance": "` + TestBalance + `"},
+	` + BuiltInContracts + `
 	"0000000000000000000000000000000000000001": {"balance": "1"},
 	"0000000000000000000000000000000000000002": {"balance": "1"},
 	"0000000000000000000000000000000000000003": {"balance": "1"},