diff --git a/cmd/lotus-shed/chainwatch.go b/cmd/lotus-shed/chainwatch.go
new file mode 100644
index 00000000000..a7435a63fa6
--- /dev/null
+++ b/cmd/lotus-shed/chainwatch.go
@@ -0,0 +1,383 @@
+package main
+
+import (
+	"container/list"
+	"context"
+	"database/sql"
+	"fmt"
+	"hash/crc32"
+	"strconv"
+	"sync"
+	"time"
+
+	"github.com/ipfs/go-cid"
+	"github.com/urfave/cli/v2"
+
+	"github.com/filecoin-project/lotus/api"
+	"github.com/filecoin-project/lotus/chain/store"
+	"github.com/filecoin-project/lotus/chain/types"
+	cliutil "github.com/filecoin-project/lotus/cli/util"
+)
+
+var chainwatchCmd = &cli.Command{
+	Name:  "chainwatch",
+	Usage: "lotus chainwatch",
+	Flags: []cli.Flag{
+		&cli.StringFlag{
+			Name:    "db",
+			EnvVars: []string{"CHAINWATCH_DB"},
+			Value:   "./chainwatch.db",
+		},
+	},
+	Subcommands: []*cli.Command{
+		chainwatchRunCmd,
+		chainwatchDotCmd,
+	},
+}
+
+var chainwatchDotCmd = &cli.Command{
+	Name:      "dot",
+	Usage:     "generate dot graphs",
+	ArgsUsage: "<minHeight> <toseeHeight>",
+	Action: func(cctx *cli.Context) error {
+		st, err := cwOpenStorage(cctx.String("db"))
+		if err != nil {
+			return err
+		}
+
+		minH, err := strconv.ParseInt(cctx.Args().Get(0), 10, 32)
+		if err != nil {
+			return err
+		}
+		tosee, err := strconv.ParseInt(cctx.Args().Get(1), 10, 32)
+		if err != nil {
+			return err
+		}
+		maxH := minH + tosee
+
+		res, err := st.db.Query(`select block, parent, b.miner, b.height, p.height from block_parents
+    inner join blocks b on block_parents.block = b.cid
+    inner join blocks p on block_parents.parent = p.cid
+where b.height > ? and b.height < ?`, minH, maxH)
+
+		if err != nil {
+			return err
+		}
+
+		fmt.Println("digraph D {")
+
+		for res.Next() {
+			var block, parent, miner string
+			var height, ph uint64
+			if err := res.Scan(&block, &parent, &miner, &height, &ph); err != nil {
+				return err
+			}
+
+			bc, err := cid.Parse(block)
+			if err != nil {
+				return err
+			}
+
+			has := st.hasBlock(bc)
+
+			col := crc32.Checksum([]byte(miner), crc32.MakeTable(crc32.Castagnoli))&0xc0c0c0c0 + 0x30303030
+
+			hasstr := ""
+			if !has {
+				//col = 0xffffffff
+				hasstr = " UNSYNCED"
+			}
+
+			nulls := height - ph - 1
+			for i := uint64(0); i < nulls; i++ {
+				name := block + "NP" + fmt.Sprint(i)
+
+				fmt.Printf("%s [label = \"NULL:%d\", fillcolor = \"#ffddff\", style=filled, forcelabels=true]\n%s -> %s\n",
+					name, height-nulls+i, name, parent)
+
+				parent = name
+			}
+
+			fmt.Printf("%s [label = \"%s:%d%s\", fillcolor = \"#%06x\", style=filled, forcelabels=true]\n%s -> %s\n", block, miner, height, hasstr, col, block, parent)
+		}
+		if res.Err() != nil {
+			return res.Err()
+		}
+
+		fmt.Println("}")
+
+		return nil
+	},
+}
+
+var chainwatchRunCmd = &cli.Command{
+	Name:  "run",
+	Usage: "Start lotus chainwatch",
+
+	Action: func(cctx *cli.Context) error {
+		api, closer, err := cliutil.GetFullNodeAPIV1(cctx)
+		if err != nil {
+			return err
+		}
+		defer closer()
+		ctx := cliutil.ReqContext(cctx)
+
+		v, err := api.Version(ctx)
+		if err != nil {
+			return err
+		}
+
+		log.Infof("Remote version: %s", v.Version)
+
+		st, err := cwOpenStorage(cctx.String("db")) // todo flag
+		if err != nil {
+			return err
+		}
+		defer st.close() // nolint:errcheck
+
+		cwRunSyncer(ctx, api, st)
+		go cwSubBlocks(ctx, api, st)
+
+		<-ctx.Done()
+		return nil
+	},
+}
+
+func cwSubBlocks(ctx context.Context, api api.FullNode, st *cwStorage) {
+	sub, err := api.SyncIncomingBlocks(ctx)
+	if err != nil {
+		log.Error(err)
+		return
+	}
+
+	for bh := range sub {
+		err := st.storeHeaders(map[cid.Cid]*types.BlockHeader{
+			bh.Cid(): bh,
+		}, false)
+		if err != nil {
+			log.Error(err)
+		}
+	}
+}
+
+func cwRunSyncer(ctx context.Context, api api.FullNode, st *cwStorage) {
+	notifs, err := api.ChainNotify(ctx)
+	if err != nil {
+		panic(err)
+	}
+	go func() {
+		for notif := range notifs {
+			for _, change := range notif {
+				switch change.Type {
+				case store.HCCurrent:
+					fallthrough
+				case store.HCApply:
+					syncHead(ctx, api, st, change.Val)
+				case store.HCRevert:
+					log.Warnf("revert todo")
+				}
+			}
+		}
+	}()
+}
+
+func syncHead(ctx context.Context, api api.FullNode, st *cwStorage, ts *types.TipSet) {
+	log.Infof("Getting headers / actors")
+
+	toSync := map[cid.Cid]*types.BlockHeader{}
+	toVisit := list.New()
+
+	for _, header := range ts.Blocks() {
+		toVisit.PushBack(header)
+	}
+
+	for toVisit.Len() > 0 {
+		bh := toVisit.Remove(toVisit.Back()).(*types.BlockHeader)
+
+		if _, seen := toSync[bh.Cid()]; seen || st.hasBlock(bh.Cid()) {
+			continue
+		}
+
+		toSync[bh.Cid()] = bh
+
+		if len(toSync)%500 == 10 {
+			log.Infof("todo: (%d) %s", len(toSync), bh.Cid())
+		}
+
+		if len(bh.Parents) == 0 {
+			continue
+		}
+
+		if bh.Height <= 530000 {
+			continue
+		}
+
+		pts, err := api.ChainGetTipSet(ctx, types.NewTipSetKey(bh.Parents...))
+		if err != nil {
+			log.Error(err)
+			continue
+		}
+
+		for _, header := range pts.Blocks() {
+			toVisit.PushBack(header)
+		}
+	}
+
+	log.Infof("Syncing %d blocks", len(toSync))
+
+	log.Infof("Persisting headers")
+	if err := st.storeHeaders(toSync, true); err != nil {
+		log.Error(err)
+		return
+	}
+
+	log.Infof("Sync done")
+}
+
+type cwStorage struct {
+	db *sql.DB
+
+	headerLk sync.Mutex
+}
+
+func cwOpenStorage(dbSource string) (*cwStorage, error) {
+	db, err := sql.Open("sqlite3", dbSource)
+	if err != nil {
+		return nil, err
+	}
+
+	st := &cwStorage{db: db}
+
+	return st, st.setup()
+}
+
+func (st *cwStorage) setup() error {
+	tx, err := st.db.Begin()
+	if err != nil {
+		return err
+	}
+	_, err = tx.Exec(`
+create table if not exists blocks
+(
+	cid text not null
+		constraint blocks_pk
+			primary key,
+	parentWeight numeric not null,
+	parentStateRoot text not null,
+	height int not null,
+	miner text not null
+		constraint blocks_id_address_map_miner_fk
+			references id_address_map (address),
+	timestamp int not null,
+	vrfproof blob
+);
+
+create unique index if not exists block_cid_uindex
+	on blocks (cid);
+
+create table if not exists blocks_synced
+(
+	cid text not null
+		constraint blocks_synced_pk
+			primary key
+		constraint blocks_synced_blocks_cid_fk
+			references blocks,
+	add_ts int not null
+);
+
+create unique index if not exists blocks_synced_cid_uindex
+	on blocks_synced (cid);
+
+create table if not exists block_parents
+(
+	block text not null
+		constraint block_parents_blocks_cid_fk
+			references blocks,
+	parent text not null
+		constraint block_parents_blocks_cid_fk_2
+			references blocks
+);
+
+create unique index if not exists block_parents_block_parent_uindex
+	on block_parents (block, parent);
+
+create unique index if not exists blocks_cid_uindex
+	on blocks (cid);
+`)
+	if err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+func (st *cwStorage) hasBlock(bh cid.Cid) bool {
+	var exitsts bool
+	err := st.db.QueryRow(`select exists (select 1 FROM blocks_synced where cid=?)`, bh.String()).Scan(&exitsts)
+	if err != nil {
+		log.Error(err)
+		return false
+	}
+	return exitsts
+}
+
+func (st *cwStorage) storeHeaders(bhs map[cid.Cid]*types.BlockHeader, sync bool) error {
+	st.headerLk.Lock()
+	defer st.headerLk.Unlock()
+
+	tx, err := st.db.Begin()
+	if err != nil {
+		return err
+	}
+
+	stmt, err := tx.Prepare(`insert into blocks (cid, parentWeight, parentStateRoot, height, miner, "timestamp", vrfproof) values (?, ?, ?, ?, ?, ?, ?) on conflict do nothing`)
+	if err != nil {
+		return err
+	}
+	defer stmt.Close() // nolint:errcheck
+	for _, bh := range bhs {
+		if _, err := stmt.Exec(bh.Cid().String(),
+			bh.ParentWeight.String(),
+			bh.ParentStateRoot.String(),
+			bh.Height,
+			bh.Miner.String(),
+			bh.Timestamp,
+			bh.Ticket.VRFProof,
+		); err != nil {
+			return err
+		}
+	}
+
+	stmt2, err := tx.Prepare(`insert into block_parents (block, parent) values (?, ?) on conflict do nothing`)
+	if err != nil {
+		return err
+	}
+	defer stmt2.Close() // nolint:errcheck
+	for _, bh := range bhs {
+		for _, parent := range bh.Parents {
+			if _, err := stmt2.Exec(bh.Cid().String(), parent.String()); err != nil {
+				return err
+			}
+		}
+	}
+
+	if sync {
+		stmt, err := tx.Prepare(`insert into blocks_synced (cid, add_ts) values (?, ?) on conflict do nothing`)
+		if err != nil {
+			return err
+		}
+		defer stmt.Close() // nolint:errcheck
+		now := time.Now().Unix()
+
+		for _, bh := range bhs {
+			if _, err := stmt.Exec(bh.Cid().String(), now); err != nil {
+				return err
+			}
+		}
+	}
+
+	return tx.Commit()
+}
+
+func (st *cwStorage) close() error {
+	return st.db.Close()
+}
diff --git a/cmd/lotus-shed/main.go b/cmd/lotus-shed/main.go
index 19072dd7191..d984aa6bd33 100644
--- a/cmd/lotus-shed/main.go
+++ b/cmd/lotus-shed/main.go
@@ -26,6 +26,7 @@ func main() {
 		base32Cmd,
 		base16Cmd,
 		bitFieldCmd,
+		chainwatchCmd,
 		cronWcCmd,
 		frozenMinersCmd,
 		dealLabelCmd,